Almost There!

One more day until break and I do believe everyone is very happy for it...

Physics A and B worked on a quick investigation of pressure with depth. Folks used a gas pressure sensor to measure pressure at different depths in a fluid column and found that pressure increased with descent and the relationship was strikingly linear. We then looked at a variation of Bernoulli's equation for still fluids (P = P₀ + ρgh) and how that matched with the equation of the line generated in lab. When we get back from break, this will be where we pick up with our work on forces in fluids.

Intro Physics reviewed their work with gravitational potential energy before moving into the area of kinetic energy. Kinetic energy is associated with objects in motion and the more motion, the more kinetic energy. We looked at the formula and the different importance of mass and velocity for changing kinetic energy. We also related work to changes in an object's kinetic energy, just as we did for the potential energies. Time was taken to practice solving problems for kinetic energy and the work-kinetic energy theorem. We'll review this tomorrow and tie up loose ends before we return from break and dive into conservation of energy.

Honors Physics enjoyed their Chapter 9 - Heat exam. Next, we're moving on to Thermodynamics!

A Very Wet Day

Not the weather, but the lab work...

Honors Physics conducted a lab on Newton's law of cooling, which examined the exponential relationship associated with the cooling process. The tested water sample showed a definite exponential curve for the cooling process and we looked at the specific equation to describe that curve. The lab is not due until Friday, so you have some time to ask me any questions about the write up before you hand it in. Remember though - test tomorrow!

Physics A conducted a lab investigation for buoyant forces. We incrementally submerged a mass and saw how the buoyant force increased with additional submerged volume until the entire volume was beneath the surface. Then, we changed the density of the water (again, incrementally) and saw how buoyant force increased, also. Things to consider for your write up:

• What is buoyant force? Equation?
• Why did buoyant force increase as the mass was lowered?
• Why did the buoyant force remain the same once the mass was completely submerged?
• Why did the measured density of water differ from the accepted value? Sources of error?
• How did buoyant force change with density for the extension?
• Why did buoyant force change with density for the extension?

Physics B took time to review their circular motion and gravitation tests and their buoyant force lab before taking a look at pressure. We contrasted pressure and force and began to look at how Pascal's principle was responsible for the function of hydraulic devices. We'll pick up with that tomorrow and then begin to look at pressure changes with position in a fluid column.

Have You Ever Seen the Rain?

Great song by CCR... and appropriate for today's drizzly weather...

Physics A reviewed their circular motion and gravitation tests and then their homework for buoyant forces and density. Attention then turned towards the area of pressure. Remember that pressure is as much influenced by force as it is area, so a tremendous force may correspond to a small pressure if the area is also large. We then talked about Pascal's principle and how it applied to the area of hydraulics. In a closed container of fluid, a pressure change is experienced everywhere in all directions of a fluid. This can, with the proper equipment, be used to design a machine to give us mechanical advantage. We looked at an example problem involving a hydraulic device and you have another with your homework. Tomorrow - how pressure varies with depth in a fluid column.

Physics B worked on a lab targeting buoyant forces. A mass was incrementally submerged and it was clear that with more submerged mass, the greater the volume of displaced fluid and the greater the weight of that displaced fluid. Since weight of displaced fluid equals buoyant force (Archimedes principle), the more the mass was submerged the greater the buoyant force to which it was exposed. When the mass was fully submerged, there was no further change in buoyant force, since there was no say to increased the volume or weight of the displaced fluid. We then added salt to the water and saw that, as expected, the greater density of fluid provided a greater buoyant force. We'll go over the lab tomorrow before taking on the idea of pressure.

Intro Physics discussed their two in-class questions from yesterday and then turned attention to energy. We defined energy as the ability to do work and then contrasted energy doing work (kinetic energy) with energy waiting to do work (potential energy). We further categorized energy into mechanical and non-mechanical and discussed examples of each. Lastly, we looked at the work-energy connection. A change of energy implies work done on or by an object and work done on or by an object will produce a change in the object's energy. Tomorrow, we start to look at specific energy types starting with gravitational potential energy.

Honors Physics reviewed their latent heat homework problems before reviewing for their Chapter 10 exam which is Thursday. Tomorrow, folks will get to do a quick activity for Newton's Law of Cooling and may use the downtime during the data collection to further prepare for Thursday's test.

Countdown!

Vacation starts next week, but this week is still a full five days of learning!

Physics A and B reviewed their Archimedes Principle activity from Friday before turning closer attention to the topics of density and buoyant forces. We looked at how a fluid's density determines (along with the object's volume) the magnitude of the buoyant force acting on the object and how that, along with the object's weight, determines whether the object floats or sinks in the fluid. Remember the formulas we highlighted in class, since they are rather ignored in your textbook, for tonight's problems and make sure you can find them on the formula sheet for your future assessment (not this week). Tomorrow, B Block works on a more detailed lab for buoyancy and A Block turns attention to fluid pressure.

Intro Physics reviewed their forces in fluids test and the work with simple machines. We then turned attention to a start on reviewing the ideas of work and power with two questions on the board that folks worked on individually and then in groups. We'll go over those questions tomorrow and then take a look at how those questions relate to the concept of energy.

Honors Physics reviewed their work with specific heat and then turned an eye to latent heat. Specific heat relates to temperature change through the input or output of heat energy and latent heat takes on phase change. When a substance at a phase-change point gains or loses energy, the temperature doesn't change because the particles kinetic energy does not change. What is changing is the potential energy of the system and that does not relate to temperature. The latent heat of fusion concerns the liquid/solid phase change and the heat of vaporization concerns the liquid/gas phase change. We'll go over the homework problems in class tomorrow before starting some review work for heat and temperature.

Phryday!

Finally, we reach the end of the week! And only one more until break!!!

Physics A and B conducted an investigation that looked at Archimedes Principle and Buoyant forces. We measured weights of objects in air, their apparent weights in water, the weigh of the fluid displaced by the object and found that the apparent loss of weight by the objects indicated the weight of the displaced water and whether the object floated or sank depended on who was larger - the weight of the displaced fluid (buoyant force) or the object's weight. We'll put more flesh on this bone Monday when we look further at density and buoyancy.

Introductory Physics reviewed their labs on levers and pulleys before looking at the remaining simple machines. All machines modify force or distance and we looked at how that idea applied to the simple machines and their real-world representatives. On Monday, we'll review the machines before starting to take on energy.

Honors Physics tied work to internal energy today before looking at the property of specific heat, the amount of heat energy required to be gained or lost to change the temperature of 1 kg of substance by 1° C. With this concept, we can calculate how much heat energy a substance gained or lost to show a particular temperature change. We'll review this on Monday before taking a look at latent heat - how much energy do we need gain or lose to promote a phase change.

With Density in the Mix

Physics A and B worked on an activity centered around density, the relationship between mass and volume for a substance. For each material, the individual samples (despite their size) had the same density, as born out by the direct linear relationship of your graphs. The slope of the lines is the material's density in kg/m³. We'll go over the labs in class tomorrow as part of our start with forces in fluids.

Intro Physics worked on a lab investigation targeting simple machines. Levers and pulleys were created and tested for the mechanical advantage they provided. Remember that a machine with an MA < 1 is not a bad machine, it is simply designed to reduce effort force or increase distance. We'll discuss the lab tomorrow as part of our discussion of simple machines, but the lab itself is not due until Monday.

Honors Physics continued their review of temperature before taking some steps into heat energy. Heat is energy transferred between substances at different temperatures. It is not stored energy. As heat energy leaves a substance, the internal energy reduces and temperature declines. As heat energy enters a substance, the internal energy increases and temperature rises. We'll add the influence of work in class tomorrow before taking a look at specific heat.

Test Day Plus Heat and Machines

Physics A and B tackled their circular motion exams and turn their attention tomorrow to forces in fluids. We'll look at buoyancy, pressure with depth and the relationship between speed and fluid pressure among other things.

Intro Physics springboarded from work and power into the topic of machines. We looked at the basic function of all machines (make work easier) and discussed the force-distance tradeoff that comes with using a machine. We used real-world examples to highlight this idea and those same examples came into play when discussing mechanical advantage. Make sure you are aware of the difference between actual and ideal mechanical advantage and can use the appropriate formula to calculate this value for a machine. Tomorrow's lab will focus on levers and pulleys as examples of machines and we'll talk about the other four classic simple machines on Friday.

Honors Physics moved into the area of heat and temperature today. We connected temperature with the average kinetic energy of particles in a system and looked at the blanket topic of internal energy, which envelops both kinetic and potential energy. The potential energy piece we'll get to when we talk about phase change, but you got a hint of that in yesterday's lab. We ended the period by beginning a discussion about temperature scales and that is where tomorrow's work will commence.

Tantalizing Tuesday

Physics A and B reviewed for their Chapter 7 exam in class today. Make sure you are clear on both the conceptual and mathematical aspects of circular motion, gravity, torque and simple machines. Two requests for videos this morning, so here's one on torque and a second on gravity and centripetal force:

Intro Physics reviewed their homework for work and power and received another practice problem set for those topics. Some folks seem to have a little difficulty deciperhing word problems, so practice makes perfect! Tomorrow, we begin looking at the classic six simple machines.

Honors Physics engaged in two lab investigations during long block. The first was on the melting/freezing of water and the other targeted the heat of fusion of water. From chemistry, you probably remember that temperature change is related to a change in the average kinetic energy of the particles in a substance and phase change references a change in the potential energy of the system. The heat of fusion indicates how much that potential energy has to change per unit mass or mole for the phase change to occur and that value is the same whether we are adding energy or removing it from a substance. We'll start on heat energy in class tomorrow and the labs aren't due until Thursday, so make sure to bring any questions with you for your write up.

All Over the Map

Honors Physics enjoyed their Fluid Mechanics exam in class today and will start on heat and heat transfer tomorrow with some lab investigations that will focus on applying conservation of energy to the concept of heat.

Intro Physics began their unit on work and energy. We defined both work and power from the perspective of physics and looked at the formulas to calculate each. Time was taken to handle misconceptions about these topics such as any force does work on an object (have to be in plane of motion) and that two machines with different power ratings do different amounts of work (do same work, just in different amounts of time). We took a look at positive and negative work and how to calculate net work on an object. We'll tie both work and power into energy as we move through the chapter, but we'll take time to explore how work and power physically play out in daily life by examining the six simple machines, which is where we take up tomorrow.

Physics A worked on their centripetal force lab during today's long block. Folks studied the relationship between centripetal force, orbital radius and speed and should be able to link their lab results to the formula we used in class for centripetal force (F_c = (mv_t)r). We'll go over the lab tomorrow in class and look at your simple machines homework before reviewing for Wednesday's exam.

Physics B examined the six simple machines and how they manipulated force and distance to make work easier. We linked the concepts of mechanical advantage (both ideal and actual) and efficiency to machine function and used the law of conservation of energy to explain the force-distance trade off when using a machine and why machines can never exceed 100% efficiency. We'll go over tonight's homework in class tomorrow before starting our review for Wednesday's exam.

Now We Can Relax

Physics A reviewed their torque homework then moved onto the area of simple machines. We listed and described each, concentrating on how they manipulated force and distance to make work easier. Remember that whatever you get from a machine (more force or distance) you lost in the other variable. Machines cannot multiply both force and distance simultaneously as that would violate the law of conservation of energy. We took a look at mechanical advantage (both ideal and actual) and efficiency as ways to describe machines and why efficiency can never be more than 100% (that pesky conservation of energy thing). Monday, you'll be working on a lab focusing on centripetal force.

Which is what Physics B did during long block. This lab has you examine variables relating to circular motion - centripetal force, speed and distance - and how how they relate to each other. We'll go over the lab on Monday before hopping into the topic of simple machines.

Intro Physics worked on their forces in fluids exam and are going to start work & energy on Monday. Honors Physic reviewed for their fluid forces exam and start of heat energy on Tuesday.

Have a good weekend!

Yes, Fangirl Strikes Again

Seriously, how can people not go and see this?

Fluids Abound

Honors Physics and Intro Physics are both working on forces in fluids, albeit at different levels of complexity. Intro Physics reviewed the basics of pressure, pressure with depth, buoyancy and density in preparation for tomorrow's exam. Honors Physics took on Bernoulli's equation, which is a statement of conservation of energy in fluid systems. Using Bernoulli's equation is like using a normal ol' conservation of energy statement - assess the physical reality of the problem (horizontal pipes, still fluids, systems open to the atmosphere at one or both ends, etc), then work the basic equation to fit the situation. The continuity equation sneaks in there, too so remember that Av = flow rate to help you out for some of the problems. We'll go over the homework in class tomorrow before embarking on a review for Monday's exam. The answers to your homework sheet:

Practice 9D

1. 18 m/s, 1.7 x 10^-3 m
2. 11 m/s, 2.7 x 10⁴ Pa
3. 4.4 x 10^-2 Pa decrease

Section Review

1. 30 s
2. 16 m/s, 1.72 x 10⁵ Pa
3. 2.7 m/s, 2.32 x 10⁴ Pa

Physics A and B took on the nature of torque as the ability of a force to produce rotation. We examined how the size of the lever arm and angle of the applied force impacted the value for torque and discussed how to ascribe signs to the torque values to help calculate net torque. Tomorrow, A Block will review their work on torque and move on to simple machines. B Block will work on a lab focusing on centripetal force and hit simple machines on Monday, when A Block gets their lab period.

Mondays are So Bad

That I couldn't even post yesterday due to the trauma...

Physics A and B have been working on gravity and Newton's Law of Universal Gravitation. We looked at gravity as a centripetal force, the nature of gravitational fields and the deeper meaning of "g," the acceleration due to gravity and measure of gravitational field strength, and how we can use that identify and NLUG to calculate the weight of an object on any planet or moon. The practice you're working tonight will help you manipulate those relationships and tomorrow, we'll change gears a little and focus on torque - the ability for a force to product rotation.

Honors Physics reviewed their work from yesterday on fluid pressure (Pascal's principle, hydraulics and pressure with depth) and took a look at fluids in motion during today's class. The ideal fluid model was discussed, as was conservation of mass in fluid systems, as described by the continuity equation. We ended the period by looking at Bernoulli's principle, which related fluid speed to pressure and discussed some examples of how this played out in real life.

This was also Introductory Physics area of work. We reviewed our work with buoyant forces, then turned our attention to Bernoulli's principle. As with Honors Physics, we looked at some demonstrations showing that faster-moving fluids exhibited less pressure than slower-moving fluids and how the forces involved generated changes in the motion of the fluid. We also discussed common day examples of Bernoulli's principle such as smoke rising up a chimney or function of perfume atomizers. We also mentioned the relationship to lift in flight, but emphasized that it was not the sole reasons planes stayed in the air. If you check your Edline page under the news section, you'll find a link to an episode of the BBC radio program Cabin Pressure that touches on this issue. The program revolves around the crew of a charter plane and their shenanigans. I'll leave the link up for a while if you'd like to give it a listen. Great if you like British Humor...

Does Anyone Like Mondays?

If so, put them in a sack. That's it, just shame them by putting them in a sack...

Physics A and B discussed their lab work on pulleys from Friday before taking on circular motion in more depth. We looked at the two velocities involved in circular motion (angular and tangential) and then looked at the acceleration that reported the rate of change of these velocities (angular and tangential). Those accelerations only reflect the speed portion of those velocities, however. The direction portion of the velocities is measured by centripetal acceleration. And, since accelerations are produced by forces, we took time to look at centripetal force and will hit torque a bit later on. Centripetal force and acceleration point towards the center of a circle (regardless of orientation of the circle) and the role of centripetal force can be assumed by any force (gravity, friction, normal force, etc.). We'll go over our homework problems for centripetal force and acceleration tomorrow before looking at one force that can act as centripetal force - gravity.

Intro Physics took time to do some peer editing of their buoyancy questions before diving into a couple of challenge problems involving buoyant forces. We'll look over those on Wednesday, as well as go over tomorrow's lab dealing with buoyant forces.

Honors Physics also worked with buoyant forces today. We defined the terms 'fluid' and 'density,' then turned attention to how Archimedes used information from observations on displacement and apparent weight to form what we today call Archimedes Principle. We looked at some helpful formulas for dealing with buoyant force and related the interplay of an object's weight and the buoyant force provided by a fluid to the concept of floating and sinking. We'll go over the homework problems tomorrow before starting to take a look at fluid pressure.

So Many Labs

Physics A and B block worked on a lab investigation involving pulleys. Folks tested simple fixed and movable pulleys, as well as pulley systems, for the mechanical advantage they produced. For pulleys, the mechanical advantage (resistance force/effort force) can be determined by experimentation or by the number of supporting ropes. The simple fixed pulley had one supporting rope and an MA of 1. The simple movable pulley had two supporting ropes and an MA of 2. And so forth and so on... On Monday, we'll start our discussion of circular motion, torque and simple machines, so have those lab sheets completed.

Honors Physics conducted a lab investigation targeting buoyant forces. When an object is placed in a fluid an upward force acts on the object equal to ρ_fluidV_fluidg. Since the product of density and volume equals mass, that formula is another way to calculate weight. To determine floating or sinking, compare the forces acting on an object (weight and the buoyant force) and see who is larger. We'll discuss buoyant forces in more detail on Monday and you can use that discussion to help with your lab write-up which is due on Tuesday.

Intro Physics went over their buoyant forces problems and then worked on some questions dealing with buoyancy. We'll read these over on Monday before moving on to fluids moving due to pressure gradients and Pascal's Principle.

Test Day!

Lots of tests on deck and now that those are over, we can get back to work...

Physics A and B worked on their Chapter 6 exams. Physics A also conducted a lab investigation that centered on levers. This coming chapter looks at torque, circular motion and simple machines (along with other things), so this activity was a nice introduction to that material. Three classes of levers were designed and tested for the mechanical advantage they produced. Even within a class of levers, it could be seen that the distance between the effort force and the fulcrum, compared to the resistance distance to fulcrum, made a difference in mechanical advantage. We'll relate those distances to the idea of lever arm and bring in the concept of balanced torque to fully explain your results. Remember, no formal write-up, but do have the questions answered, including the Going Further for tomorrow.

Honors Physics had their Chapter 7 exam to enjoy and tomorrow will have folks conducting an investigation on buoyant force to start our unit of forces in fluids.

Intro Physics reviewed their work on pressure with depth before moving on to buoyant force. We discussed Archimedes work to gain knowledge about buoyant force and let Archimedes Principle explain why objects float or sink in different fluids. Floating and sinking is based on the net force acting on an object placed in a fluid and Archimedes Principle lets us establish the size of the buoyant force to add to the object's weight to get the net force. We analyzed how density plays into the calculation of buoyant force and ended the class with a series of problems on buoyant forces. We'll go over these tomorrow, before looking at some questions about buoyant forces.

Conference Day

We had an abbreviated day due to parent-teacher conferences, but some work did get done regardless.

Physics A and B reviewed for their Chapter 6 exam, with Physics B (having a modified long block), having some time to explore conservation of momentum for rotating systems. Angular momentum is another conserved value, like linear momentum, but depends on different variables. For linear speed, we have angular speed - the speed at which the object rotates. For mass, we have moment of inertia - the resistance of an object to changes in its rotation. Moment of inertia does depend on the quantity of mass present, but also on how that mass is distributed around the rotational axis. Then your hands were away from your body, your rotational speed was lower than when your hands were drawn in close. With more of your mass distributed away from the axis of rotation, the harder you were to rotate (greater moment of inertia) and with your arms drawn in, you had more mass clustered near the axis of rotation (lower moment of inertia). Low moment of inertia, higher rotational speed; high moment of inertia, lower rotational speed. The product of the two, however, would remain constant since angular momentum had to be conserved. For both blocks, after tomorrow's test, we move on to circular motion and gravitation.

Honors Physics reviewed for their Chapter 7 exam and on Friday, we take on forces in fluids.

A Full Week! Almost...

We have a half-day tomorrow due to parent-teacher conferences, but this is more instructional time in a week than we've had lately, so yeah!

Physics A and B worked on the idea of elastic collisions, building on yesterday's work with perfectly inelastic collisions. Elastic collisions conserve both momentum and kinetic energy and we worked some problems putting those ideas to use. Tomorrow we'll have some review time in preparation for Thursday's exam. Then it's on to circular motion.

Intro Physics spent time discussing yesterday's density investigation and used that to springboard into the concept of pressure variations with depth in a column of fluid. As we descend in a fluid, pressure increases and as we ascend, pressure decreases. We contrasted gauge and absolute pressure and ended the class by starting on some problem-solving practice with these ideas. We'll go over the homework at the start of class tomorrow before looking at buoyancy and buoyant forces.

Honors Physics worked on an activity to demonstrate the action of simple machines to multiply effort force of distance. Three classes of levers were tested for the mechanical advantage they produced and how they make work easier. We'll go over this activity tomorrow before reviewing the simple machine homework and reviewing for Thursday's exam. Then - forces in fluids!

Being a Fangirl

No explanations... no apologies...

Meeting the Challenge

Physics A and B reviewed their conservation of momentum homework and were then challenged to solve a conservation of momentum problem involving 2-dimensional motion. Groups worked hard, with the first ones to solve the problem winning a valuable prize. Kudos to those groups who tackled this successfully! On Monday, we'll review conservation of momentum, then turn our eyes to applying this concept to specific types of collisions.

Intro Physics had about 47 seconds in class before they were called down to the pep rally. On Monday, we'll start the density investigation that was introduced in these paltry 47 seconds of class time.

Honors Physics didn't meet because of the half-day. On Monday, we'll review the concept of torque and then begin to look at the simple machines.

Have a great Thanksgiving!

Force, Torque, Pressure and Momentum

Folks are in very different places today, but everyone is moving along nicely...

Physics A and B reviewed their work with the impulse-momentum theorem before turning attention to conservation of momentum. Conservation of momentum comes about through Newton's 3^rd Law of Motion - the impulse that acts on one object has to match the impulse that this object imparts to the object that touched it. Therefore, the momentum changes of each object are equal but opposite. One object gains momentum and the other loses it, but the total remains the same. Momentum is simply transferred between objects in the system. We looked at examples of situations from the perspective of conservation of momentum to highlight strategies for problem solving and folks worked some practice in class. We'll go over the homework practice tomorrow and toss in a little extra if need be to nail this concept down.

Intro Physics continued their discussion of Pascal's Principle and hydraulic devices. We looked at how hydraulic devices serve to multiply our effort force (something we'll later call mechanical advantage) and how to calculate the size of that force multiplication. Time was given in class to work problems involving hydraulic devices and tomorrow, depending on how much time we have with the pep rally stealing our instructional time, we may or may not do an investigation on density. We'll need a good understanding of density to work through the upcoming topics of pressure with depth and buoyant forces.

Honors Physics reviewed their work with Kepler's laws of motion and yesterday's lab on centripetal force before taking on the concept of torque. Torque is the rotational analogue of force - it serves to change the speed of rotation (produces angular acceleration). Centripetal force handles direction and torque handles speed in the rotational world. We looked at some demonstrations of how force and torque differ and how the angle through which the force is applied affects a force's ability to rotate an object. Your homework items will give you practice with torque, lever arm and rotation and we'll revisit these ideas on Monday when we start to look at simple machines.

Turkey Week!

Another short week and yes, that is something for which to be thankful...

Physics A and B used their lab work from last week to illustrate ideas associated with momentum and momentum change. We defined momentum and looked at how a change of an object's momentum can be linked to the combined effects of force and time. The product of those two is termed 'impulse' and this leads to the impulse-momentum theorem. We discussed how Newton's laws of motion stem from changes in momentum and the relationship to force and time, how stopping times and distances can be assessed using the impulse-momentum theorem and how areas such as sports and safety equipment use impulse-momentum to promote desired effect on objects or bodies. Tomorrow, we'll collect those labs and then take a look at conservation of momentum (made possible by good old Newton's 3^rd law of motion.

Honors Physics worked on a lab that linked centripetal force, orbital radius and orbital speed. Larger radii need higher orbital speeds to be maintained, given the same centripetal force and greater centripetal forces require greater orbital speeds to maintain a constant orbital radius. We'll discuss the lab tomorrow, along with the work on Kepler's laws of planetary motion, before moving on to torque - the rotational analogue of force.

Intro Physics began class by reviewing their force and momentum exam then turned attention to the action for forces in and on fluids. Pressure was defined as force/area and the generation of internal pressure by fluids was described. We looked at common events that are promoted by differences in fluid pressure between two areas (like breathing and drinking through a straw) and just dipped our toes into hydraulics before the bell cut our time short. We'll pick up there tomorrow and get some practice working with the math of pressure and hydraulic devices.

If You Understand This...

...you understand the profound things in life...

Ending a Short Week

Only to begin another one on Monday. Not that I'm complaining...

Physics A and B both completed their Impulse-Momentum lab today. We start our unit on momentum and collisions on Monday and we'll get some more information on impulse and its relationship to momentum at that time. Labs are due on Tuesday, so use Monday's information to help round out your conclusions.

Intro Physics enjoyed their Chapter 11 exam. On Monday, we're sticking with forces, but looking at how they interact with fluids.

Honors Physics reviewed their work with Newton's law of universal gravitation and then tied that law to Kepler's laws of planetary motion. Make sure you are clear about what each of Kepler's laws has to say and can work with the math, calculating period, mass and/or orbital velocity. We'll review this on Monday before shifting gears a little and taking on the topic of torque.

Forces and Momentum

Despite being in very different places, all classes are working somehow in the arena of force or momentum.

Physics A and B enjoyed their Chapter 5 exam and Physics B moved after the exam, being long block, to a lab that looked at the impulse-momentum theorem. An object's change of momentum is dependent of the net force acting on the object and the length of time that the force acts. Mathematically: F_netΔt = Δp. We'll finish up the lab tomorrow and A Block will start on it during their long block.

Introductory Physics reviewed their forces and momentum MCAS review work and also engaged in a general review of these topics in preparation for tomorrow's exam. On Monday, we'll start to expand our work on forces by looking at forces in fluids.

Honors Physics reviewed their work with centripetal force and acceleration, then took a look at one specific force that can act as a centripetal force - gravity. We discussed Newton's law of universal gravitation how it can be applied. The link between acceleration due to gravity and gravitational field strength was broached, as was the effect of gravity on orbital motion and the tides. Tomorrow, our heads stay in the heavens as we take on Kepler's laws of planetary motion.

Wonderful Wednesday

On top of being a beautiful day, everyone had a busy class period.

Physics A and B reviewed for their Work and Energy exam. I had a request, and it was a good one, for a video centering on power and how to choose the right formula/relationship to solve problems. So, here's that video and remember that there were a couple of posted earlier on calculating individual forms of energy and solving problems using conservation of energy:


Introductory Physics reviewed their momentum quiz before moving on to some MCAS review for forces and momentum. We'll use these questions/problems as part of tomorrow's review for Friday's exam, so do your best with them!

Honors Physics began a unit for circular motion. We discussed how the speed of circulation motion can be described and contrasted angular and tangential velocity. If velocity changes, that means acceleration and we discussed three accelerations associated with circular motion, two which report rate of change of the speed portion of velocity (angular and tangential acceleration) and the other that reports the rate of change of the direction part of velocity (centripetal acceleration). Tangential and angular acceleration are in the direction of the velocity in of the motion, but centripetal is always pointed towards the center of the circular path. Centripetal acceleration is produced by centripetal force, which is a job description not the name of one specific force. We looked at examples where tension, gravity, friction and the normal force can all act as a centripetal force, so look for all of those to possibly show up in problem solving. Tomorrow, we'll keep going with circular motion by looking at one specific force that can act as a centripetal force - gravity.

I Didn't Want to Come Back To This

Nice, fun, long weekend and we come back to cold, rainy misery. Not really worth getting out of bed, was it?

Regardless, it was a busy day all around. Physics A and B reviewed their work on conservation of momentum and then looked at the concept of power. Remember that power is a rate function: the rate at which work is done, the rate at which energy is transformed, the rate at which energy us used, etc. A machine with a higher power rating than another doesn't do more work than the latter, it only does the work faster. The practice problems took us a bit longer than expected, so we pushed tomorrow's test back to Thursday and will use all of tomorrow for review. On Friday, we begin our unit on momentum, with A Block discussing the nature of momentum and impulse and B Block working on a lab targeting the impulse-momentum theorem.

Introductory Physics completed their impulse-momentum theorem labs, which are due on Monday so you have plenty of time to get help with the calculations or the writing before you hand it in for credit. Tomorrow, we'll go over the momentum quiz and begin working on items from previous MCAS exams centering on forces and momentum. We'll go over these on Thursday and have a general chapter review before having our exam on Friday.

Honors Physics enjoyed their Chapter 6 (Momentum and Collisions) exam and will start with circular motion and gravity tomorrow. It will be a change of gears, but will broaden our model of motion quite nicely.

Videos

Couple of videos for Physics A and B. First is on calculating types of mechanical energy and working with work-kinetic energy theorem. Second is about conservation of energy. Have fun!

Marching into the Weekend

Physics A and B reviewed their work with potential energy and then turned attention to conservation of energy. We had our lab work in this area to draw upon for examples of how energy transformed into different forms/types and how these transformations did not in any way change the total amount of energy present in the system. When friction is a big player in the game, conservation of mechanical energy can be very poor, but when friction is well controlled, we can see good conservation of mechanical energy. Conservation of total energy always holds, though, even if some is turned to non-mechanical forms. On Tuesday, we'll quickly add power to our bag of tricks and begin the review process for Wednesday's exam.

Intro Physics took their momentum quiz and then moved on to a lab that dealt with the impulse-momentum theorem. with a force sensor and motion detector, data could be collected for force, time and velocity which, with the mass of the cart, put together a nice picture of how the impulse acting on an object produced a change of the object's momentum. Folks are testing loose elastic materials, producing a long time interval for the force to act and stiffer materials that have forces act on the object for a much shorter time. We still have data to collect and analyze and that's what we'll work on when ewe come back on Tuesday.

Honors Physics went over their collisions homework before walking through the chapter in preparation for Tuesday's exam. On Wednesday, we shift gears a bit and start to tackle circular motion.

Have a great long weekend!

Snow!

The first snow of the year and it actually stuck! That does not bode well for my hope for an easy winter...

Physics A and B reviewed their Chapter 4 tests and their work/work-kinetic energy theorem homework before turning attention to potential energy. We looked at two energies of position, gravitational potential energy (PE_g) and elastic potential energy (PE_e), the same two on which we focused during our recent lab investigations. Make sure you know what goes into calculating each energy type, their connection to work and that each can change depending on the situation. We'll look more at those energy changes when we take on conservation of energy tomorrow.

Introductory Physics had more practice working with the math of conservation of momentum today in class. You can't really give a formula for conservation of momentum besides p_i = p_f, because the physical nature of the circumstances will have you script that relationship differently for each scenario. The key is to think about the relationship itself and use your knowledge of the problem to write down the members for initial momentum and final momentum. Tomorrow, a quick quiz on impulse-momentum and conservation of momentum before we conduct a lab investigation on the impulse-momentum theorem.

Honors Physics reviewed their work with conservation of momentum before detailing aspects of specific types of collisions - perfectly inelastic, inelastic and elastic. For all, momentum is conserved; however kinetic energy is conserved only for elastic collisions. We'll review the chapter material tomorrow and look to Tuesday for our Chapter 6 exam.

And We Return

Students had a nice day off yesterday, while teachers suffered through a professional development day. I'd much rather be teaching...

Physics A completed the data collection and analysis for their energy conservation labs. Some conclusion ideas for the lab, which is due on Friday:

• What does each form of energy entail - what goes into measuring each type (height, speed, etc.)
• What patterns of change did you see and why did those patterns occur (did speed increase, stretch decrease, etc.)
• How did one pattern of change in one energy form relate to the pattern of change in the other.
• What is conservation of energy and how does it play into the observed patterns of change for the energies?
• Did friction play a role? Why or why not?
• Sources of error? What were they and how might they have impacted the results?

Physics B reviewed their energy conservation labs and their discussion on work before moving on to kinetic energy and the work-kinetic energy theorem. We defined energy as the ability to do work and related positive and negative work to an object's energy bank. The formula for kinetic energy was examined, with a note on the greater importance of velocity on an object's kinetic energy, then turned attention to linking quantitatively an object's energy change and work. We'll review this tomorrow, before adding more energy types to our list of suspects.

Introductory Physics reviewed their problems for the impulse-momentum theorem before taking on conservation of momentum. The momentum of a system stays the same, as long as outside influences are not acting (like friction). We looked at examples of conservation of momentum before staring to work on the problem-solving aspect with a few samples. More practice tomorrow in preparation for a quick quiz on Friday before our lab on momentum.

Honors Physics conducted an investigation on the impulse-momentum theorem. A force sensor measured force applied to a moving cart and a motion detector tracked the cart's velocity change. With this information, along with time, comparisons between impulse and the cart's momentum change can be compared. We'll talk about the lab in class tomorrow, but the write-up isn't due until Friday. Tomorrow's discussion will dissect types of collisions and relate them to conservation of mechanical energy and momentum. Friday - review. Monday - Exam. Tuesday - Circular motion and gravitation.

Energy and Momentum

Physics A completed their conservation of energy labs and we'll pick up on Wednesday with a discussion of those labs and a more detailed look at kinetic energy. Physics B started these labs and folks are in varying stages of complete, so we'll take Wednesday for tying up all loose ends before moving on to potential energy on Thursday.

Intro Physics reviewed their quiz from Friday and then moved on to momentum. Make sure you can differentiate between momentum and inertia, calculate the momentum of an object given mass and velocity, recognize and work with the vector nature of momentum and solve problems using the impulse-momentum theorem. When a force acts on an object, the duration of time that force acts makes a big difference in the object's change of motion. We looked at the math behind the impulse-momentum theorem and how it explained the need for follow-through in sports and function of safety gear such as air bags and safety nets. Tomorrow, we'll look at conservation of momentum and start more math with that concept.

Honors Physics reviewed their impulse-momentum work and then moved on to conservation of momentum. In a system, barring outside influences, the momentum of the system is conserved. Each interacting object will show a momentum change, but the total value remains constant. We looked at how Newton's 3^rd law of motion and the concept of impulse accounted for conservation of momentum, then began to work problems involving conservation of momentum. On Wednesday, folks will work on a lab centered on the impulse-momentum theorem and we'll continue on with conservation of momentum on Thursday.

Phunky Phryday

Physics A continued with their discussion of work to add the connection between work and energy. We discussed the general definition of energy (the ability to do work) and concentrated on kinetic in today's lecture. Kinetic energy is associated with motion, so if you are at rest, you have 0 Joules of kinetic energy. If you experience an increase of kinetic energy, it's most likely that you increased you speed. Increasing speed reflects positive work being done on you and the amount of work done will equal the kinetic energy increase. Negative work would reduce your speed and, therefore you're kinetic energy. Again, though, the amount of work will equal the kinetic energy change. That relationship is called the work-kinetic energy theorem, but can be expanded to relate work to any energy form. On Monday, you'll work on a lab that allows you to investigate the types of mechanical energy in this chapter and also introduce you to the concept of conservation of mechanical energy.

Physics B conducted their energy transformation/conservation labs today during long block. Transformations between KE and PE_g and PE_e were tackled between two investigations. Throwing in a ball in the air demonstrates the trade-offs between height and speed and the related energy changes, and an oscillating spring highlights speed and displacement tradeoffs, again relating to energy. However, at all times, as your graphs showed, total energy is conserved. We'll discuss this lab on Monday before taking on kinetic energy and its relationship to work.

Intro Physics enjoyed their quiz on the math of forces. We'll go over those on Monday and begin our discussion of momentum. The paragraph you're to write for homework is described on Edline if you didn't jot it down in class and be prepared to share your thoughts with others in class next week.

Honors Physics went over their Chapter 5 tests, then began a discussion of momentum. Momentum was once considered the quantity of motion and it was in light of momentum that Newton thought about forces and changes of motion. We defined momentum, showed how mass and velocity had equal roles in determining an object's momentum and discussed the impulse-momentum theorem, which links force and motion through the aspect of time. We'll get some lab work with this concept next week and also go deeper into momentum by examining the concept of conservation of momentum.

Child's Play

Every year I beat the drum for the Child's Play charity. It is totally the type of charity I can get behind - one where all the funds go to the charity's target (sick children) and not to administrative salaries and other things that don't help anyone but the fat cats. Child's Play is a organization that calls on gamers to show the world we're not all pale, weird, freaks living in our parent's basement or out of control violence-eaters the way the media likes to make us appear.

Each year, a massive fundraising effort gets underway. There are hosts of events in which to participate to raise money and you can even set up and run your own event like a gaming marathon. Folks can also donate directly to a hospital through PayPal or using the hospital's Amazon Wish List. Everything goes directly to the hospital - no middleman. I always throw support towards the Children's Hospital in Boston, but have, when funds allow, given to other hospitals that probably don't get as much support, such as hospitals in Egypt and New Zealand.

If you game or even if you don't, you might consider Child's Play if you're looking for a charity to support. I keep a link on the sidebar during the donation season, but they take contributions all year long. To learn more about Child's Play, visit their website: http://childsplaycharity.org

Gamers can make a difference. A good difference. Millions of dollars, to date, of a difference. Feel free to join the party...

Finalizing Forces

Well, not really, because they'll haunt us all year like Marley's ghost, but at least that particular section is finally being put to bed.

Introductory Physic reviewed the math associated with forces and the resulting acceleration an object experiences. Tomorrow's quiz will target the quantitative face of Newton's 2^nd law of motion, Newton's law of universal gravitation, calculation of net force, weight and kinematics involving falling objects (and horizontally-moving objects if it relates to other topics). On Monday, we'll start on momentum!

Physics A and B began their unit of work and energy. We put a specific scientific definition to the term work and looked at situations where forces did and not do work on objects. We talked about W_net and how it is calculated for a variety of situations and what it meant for work to be positive or negative. Physics A will start connecting with work in class tomorrow. Physics B will do the same, but with two lab investigations.

Honors Physics enjoyed their Chapter 5 exams and will take on momentum and its conservation starting tomorrow.

Happy Halloween!

And a special shout out to all those who dressed up to celebrate...

Physics A and B Blocks enjoyed their Chapter 4 exam and will start with work and energy tomorrow. For your homework, remember that I am looking for how you use the terms work, power and energy, not how a scientist might use them. We'll add that part in class, but take time to think about what meaning or meanings you give those words. We'll share ideas tomorrow before starting in on work.

Introductory Physics reviewed their acceleration due to gravity and air resistance labs. We also took time to review the protocol for writing the lab synopsis and how to properly script a solid conclusion section. We then hopped into Newton's 3^rd Law of Motion to conclude our discussion of good ol' Isaac (for now). Do your best not to succumb to the pitfalls of interpreting N-3. N-3 talks about the forces that arise during interactions, not the results for the objects in the interactions. That's N-2's job. The forces arise simultaneously, despite the time-lag implications of the term action-reaction forces. Lastly, the equal and opposite forces act on different objects and, therefore, are not the forces we talk about in a discussion concerning equilibrium. We'll review Newton's laws and our ideas about free fall/gravity in preparation for Friday's quiz. That quiz will center on the math of this section of work, so be prepared to button-punch that calculator!

Honors Physics went over their work on power, then turned to a review for tomorrow's Chapter 5 exam. On Friday, we'll start in on momentum and conservation of momentum. We won't be leaving the idea of forces and energy, so keep those topics in an easily accessible room in your mind palace.

The Aftermath

Well, there really is no aftermath. The storm was fairly lackluster for this part of the world, so we are back to normal.

Physics A and B reviewed for tomorrow's exam for Chapter 4. Remember to look at the videos posted a few days ago for problem-solving information for forces on objects on horizontal surfaces and on inclines. Starting Thursday - Work and Energy.

Honors Physics reviewed Friday's homework problems, then turned attention to power. Remember that power measures the rate at which work is done or energy is converted/used. Two machines with different power ratings can do exactly the same amount of work. The difference is that the higher-power machine will do the work in a shorter time period. Calculating power can take a variety of pathways - using work and time; using energy (KE or PE) and time; using net force and velocity. So, read problems carefully to plan a strategy to use power relationships. Tomorrow, review for the Chapter 5 Test, Thursday is the Chapter 5 test and Friday finds us entering the domain of momentum.

Introductory Physics conducted two lab investigations today. One looked at measuring the value for acceleration due to gravity, which we accept as 9.81 m/s² as an average. Because the value is an average, we don't expect classroom values to necessarily fall directly on that value and, although it is minimal, there is the impact of air resistance to consider. The second lab looked at air resistance specifically, and how it influenced the motion of an object as it fell. We'll go over these labs tomorrow, but the write-ups aren't due until Friday. Tomorrow, we'll tidy last minute issues for free fall and projectile motion and move on to Newton's 3^rd law of motion.

Needless to Say...

...all exams have been pushed back one day since we are not in school today. I'm still waiting for something to warrant all of this fuss, but perhaps I'm just jaded.

Growing up in Louisiana makes me a little hard to please in terms of storms. I've endured enough full-swing hurricanes, tropical storms and tornadoes that things have to get pretty bad to make a blip on my radar. That doesn't mean I don't approach things rationally, though. I never buy or rent a residence that has electric heat, and electric stove or an electric hot water heater. We lost power frequently when I was a kid and having the ability to stay warm, have a hot meal and shower was always a blessing. When the storm warnings hit, I dig out my battery-powered radio, flashlights, candles and old-fashioned phone. Knowing I'll have some light to read, the ability to listen to music and news and make phone calls in the event of an emergency is a good thing. I also make sure all electronic devices are fully charged and my back-up power supplies are also charged to the brim. Fresh water is hoarded, dog food is stockpiled and then there's coffee. Growing up, there was no Mr. Coffee or Keurig machines. Coffee was made in a coffee pot, set in a pot of water on the stove. I still have that equipment stashed away, ready to be put to use when power fails. All possible projectiles such as garbage cans and bird feeders have been stowed and all clothes and dishes have been washed, in case that ability is lost for a few days. Yeah, the storm isn't worrying me, but I'd rather put a little effort into hedging my bets than a lot of effort trying to keep body and soul together if I've misread Mother Nature.

Stay safe and, hopefully, I'll see everyone tomorrow!

Videos

Physics A and B have a test Tuesday that focuses on forces. Here's a couple of videos about the topics we've been hitting the past couple of days...

A Taste of Spring

...or springs, in the case of Honors Physics. Today's warm temps made staying inside and actually being school-y very difficult, but folks diligently conducted their lab investigations on energy conversions and conservation of energy. The Ball Toss lab demonstrated the conversion between kinetic and gravitational potential energies and the Energy of Simple Harmonic Motion lab tracked transformation between kinetic and elastic potential energies. The graphs very nicely showed that when one form of energy decreased, the other form increased by an equal amount, keeping the total amount of mechanical energy constant. We'll go over the lab on Monday, as well as the homework problems for conservation of energy before taking on the topic of power.

Physics A had a discussion about friction during today's class period. The origin of frictional forces was described, with static and kinetic friction being contrasted in terms of role in motion and magnitude. The coefficient of friction was introduced as a way of evaluating the role of surface materials in determining frictional resistance and the calculation of frictional force and net force was practiced in class. This latter bit was the focus of Physics B's work and we made our way through a variety of problems showing how to integrate friction into problems involving the motion of objects. Monday is general review day, so come with questions, and the Chapter 4 exam still falls on Tuesday. On Wednesday - Work and Energy!

Introductory Physics folks spent the period discussing projectile motion. We defined projectile motion, differentiated between situations where objects were and were not moving as projectiles, explored the general features of projectile motion and practice problems solving for aspects of the motion of horizontally-launched projectiles. We'll review this on Monday, before turning attention to the last of Newton's laws of motion - Newton's Third.

Forces Abound

Physics A worked on a lab that targeted Newton's 2^nd law of motion. We looked at how varying force (with mass constant) and mass (with force constant) impacted acceleration. Keep the basic statement of N-2 in mind as you script your write up (due Monday), but here are some general ideas for material for your conclusion...

• What does Newton-2 say, conceptually and mathematically, about the relationship between net force, inertia and acceleration? Does your data support this concept? Why or why not?
• What was the net force in this experiment? How would friction impact your results.
• Sources of error? What issues or problems might have contributed to any aberrant data points for your group?

Physics B spent time discussing friction during today's class. We looked at the origin of frictional forces (surface imperfections and adherent electrostatic bonds) and explained why static friction maximum (F_s,max) was larger than kinetic friction (F_k) for any pair of surfaces. The coefficient of friction was introduced and some examples were discussed to better clarify what the coefficient of friction meant for frictional resistance. Tomorrow, we'll go over the homework problems, then get more practice with friction, weight, normal force and net force in preparation for Tuesday's exam.

Introductory Physics had only a few minutes of class time today, due to Peer Mentor stuff, so all we had time for was a quick review of the free fall and kinematics homework. Tomorrow, we'll dig deeper into the impact of free fall on motion by getting a peek at the mechanics of projectile motion.

Honors Physics reviewed the concept of mechanical energy and how it is related to work before jumping into conservation of energy. Total energy is always conserved in systems, but mechanical energy is not. Friction always converts some useful energy into heat, which is non-mechanical and not easily accessible for work, thereby reducing the overall useful mechanical energy in the system. Tomorrow's two lab investigations will have folks looking at conservation of mechanical energy in situations where all of our mechanical energy types (to date) play a role.

You Should Just Fess Up

No one has come forward to claim responsibility for my illness and that's just chicken-baby behavior, if you ask me. So, I get to suffer without retribution against the perpetrator, which would make me feel much better...

Physics A reviewed the concepts of weight and the normal force and got extra practice calculating the normal force for a variety of situations. We'll get back to specific forces on Friday, but tomorrow is set aside for a lab that lets folks examine the tenets of Newton's 2^nd law of motion. Physics B conducted that lab today and found that, barring the normal noise in the data, there was a direct relationship between the applied force and the cart's acceleration and an inverse relationship between the cart's inertia and the acceleration (when the applied force was held constant). We'll address any problems or questions for the lab tomorrow, before turning attention to friction.

Introductory Physics reviewed their work with weight and free-fall before getting some focused practice on the kinematics of free free fall. We'll go over those problems tomorrow in class, before adding a layer of complexity to our discussions by looking at orbital or projectile motion.

Honors Physics got a quick review of mechanical energy and were allowed class time to work on problems/questions dealing with kinetic energy, gravitational potential energy, elastic potential energy and the work-energy relationships. Tomorrow, we'll take a look at conservation of energy - a powerful tool for problem solving when the acceleration of an an object cannot be assumed to be constant.

Just Who Gave Me This Cold?

Someone is going to get the stink-eye from me if I find out who transmitted their plague germs into my personal bubble. Hopefully, I shall not be brung low by this pestilence, but we shall have to see. I am made of stern stuff, after all...

Physics A and B Blocks have been marching through Newton's laws of motion and a few specific forces. Remember that Newton's laws of motion state what objects do when exposed to a zero or non-zero net force and also point a finger at the culprit(s) providing that force. Two of those culprits could be weight and the normal force. Weight is the action of gravity on an object's mass and the normal force is the response of a surface to a press onto it. That response is always perpendicular to the plane of the surface and may or may not line up with the object's weight (which is always straight down). We looked at how to calculate the normal force acting on an object and we'll check over that work tomorrow before diving into friction. Exam coming up next Tuesday and we have a lab to conduct on Newton's 2^nd law in the interim, so start gathering questions and making study preparations so you can do your best on the test.

Honors Physics has been discussing the concepts of work and energy. We disentangled the scientific definition of work from how the term is used in daily life and identified examples where objects were having work done on them by a force and when a force was not doing work on the object. W_net was linked to an object's motion and change/lack of change of motion and further linked, today with the change in energy an object experiences. We defined kinetic, gravitational potential and elastic potential energy and discussed how a change in each of them related to the work that was done on or by an object. We'll look at this some more tomorrow before moving more deeply into energy territory.

Introductory Physics has been laboring with gravity. We looked at Newton's law of universal gravitation yesterday from a conceptual and mathematical standpoint and, today, added in the concepts of free fall, weight and acceleration due to gravity. Remember that free fall only applies when there isn't another force acting on the object's motion besides gravity, such as air resistance, so it isn't applicable to all circumstances. However, many objects moving through the air do approximate free fall and it can be a good predictor for features of the object's motion, such as how high the object rises when thrown upwards or fast it will hit the ground when it is dropped. We'll practice with this idea tomorrow and begin to look at a slightly more complicated model of motion - projectile motion.

Forceful Friday

Physics A reviewed their work on the basic properties of forces and free-body diagrams and then turned attention to Newton's 1^st law of motion. N-1 states that objects continue with whatever motion they are currently experiencing unless a net external force acts on them. We linked the idea of inertia to this law and discussed how mass is the direct measure of an object's inertia. We also took time to define and explain the concept of equilibrium and how equilibrant forces are calculated On Monday, we carry on with Newton's 2^nd law of motion, which will let us quantify the value of acceleration caused by a net force.

Which is what Physics B did today. We discussed, both conceptually and quantitatively, Newton's 2^nd law of motion and spent time working practice problems to calculate the net force acting on an object and, subsequently, the object's acceleration. We'll practice this a little more on Monday, when we add Newton-3 to our list, but have to return to Newton-2 to put some numbers to our situations.

Introductory Physics conducted a lab investigation centering on Newton's 2^nd law of motion. Newton-2 states that there is a direct relationship between an object's acceleration and the net force it experiences and an inverse relationship between acceleration and the object's inertia, measured by its mass. We tested the acceleration of a cart, where the net force remained steady, but the cart's inertia changed and also the acceleration of a constant-mass cart when the net force was allowed to vary. We'll discuss this lab on Monday, but remember that the lab write up is not due until Tuesday.

Honors Physics basked in the glow of their Chapter 4 exams and will pick up with Chapter 5 - Work and Energy - on Monday.

Have a good weekend!

Continuing on With Forces

Physics A went over their Chapter 3 exams, then turned attention to forces. We discussed the nature of forces, the difference between contact and field forces and the use of free-body diagrams to document the forces acting on an object. We'll use those free-body diagrams tomorrow to help us with our calculations of net force acting on an object. Physics B did this yesterday and was supposed to move on to Newton's 2^nd and 3^rd laws of motion, but we took extra time to go over the test and homework, so that will be the focus of tomorrow's work.

Honors Physics reviewed their lab investigation and also the last batch of homework before addressing any last-minute issues for tomorrow's exam. If you need more discussion about the latter problem types, don't forget to check out the videos that were posted yesterday. Monday - Work and Energy!

Introductory Physics reviewed their Chapter 10 exams and then turned attention to more concepts associated with forces. Newton's 1^st and 2^nd laws of motion. The 1^st law of motion describes how the motion of an object is governed by its inertia until the object is acted upon by a net external force. Even if forces act on the object, if the F_net = 0, the object's remains unchanged. We then took a look at the 2^nd law to discover a way to assess the magnitude of the object's change of motion. The acceleration an object experiences is directly proportional to the F_net and inversely proportional to the object's inertia, measured by its mass. The equation associated with Newton-2 (F_net = ma is the quantitative way of assessing the size of the object's acceleration or or applied external force. Tomorrow, we'll check over the homework problems, add a few more for practice, then turn our attention to a specialized acceleration - acceleration due to gravity - and how it is involved with a specialized force known as weight.

The Force is Strong

Physics A completed their Static and Kinetic Friction lab today and the write up is due on Friday. Hopefully, you took a look at the hints I put on the board for your Conclusion section and are going to take a sneak peek at the friction section of this chapter to help make meaning of your results. Tomorrow, we'll start on a discussion about the nature of forces.

Physics B used their work with the nature of forces to make an inroad into Newton's laws of motion. We tackled Newton's 1^st in class today and got some practice problem solving using N-1. Make sure you fully understand the implications of Newton's 1^st and that you can use the free-body diagrams you practiced yesterday to calculate the net force acting on an object. Tomorrow, we'll see how to calculate the acceleration that force produces in conjunction with another topic we discussed today - inertia. Keep in mind that inertia is measured by an object's mass and nothing else. That will help when we work with Newton's 2^nd law tomorrow.

Introductory Physics enjoyed their graded learning experience for Chapter 10 this afternoon. Tomorrow, we'll go over that exam and start to head deeper into the great Force Forest.

Honors Physics conducted a lab that had folks investigating both static and kinetic friction. We measured these values using both a force sensor and a motion detector, and used the information to calculate coefficients of friction. We'll discuss the lab tomorrow as part of our Chapter 4 review, but the write up is not due until Monday. Overall, tomorrow is set aside for exam preparation, so come with questions. As promised, I put together a few videos for working with that pesky net force-acceleration situation:

Easiest

In the Middle

Hardest

Fiddling with Forces

Physics B discussed yesterday's friction lab before jumping into our new unit on forces. Friction is a specific force, but it does what all forces do - act to accelerate objects. We discussed the idea of net force (F_net) and what it meant when F_net = 0 N and ≠ 0 N. You should be able to calculate the net force acting on any object and be prepared to draw a free-body diagram to document the forces that were included in the net force calculation. Remember that forces can be contact forces, like a physical push or pull, or field forces, like gravitational or magnetic forces, but they do the same job and contribute to net force calculations. Tomorrow, we'll start to specifically line forces to motion and changes in motion as we dive into Newton's laws of motion.

Physics A started a lab investigation on static and kinetic friction. Static friction acts on objects at rest on surfaces and kinetic friction acts on objects in motion across or through surfaces. Both frictional forces arise from irregularities on the surfaces of the materials in contact, but static friction is boosted by the formation of adhesive, electrostatic bonds between the surfaces. Because of this, for the same objects in contact, the peak static friction (F_s,max) will always be greater than the kinetic friction (F_k). The data you are collecting is showing this relationship nicely and slotting in the additional concept of coefficient of friction. We'll talk about that tomorrow as more groups get to that calculation and discuss what it means specifically for our surfaces in the experiment.

Introductory Physics reviewed their MCAS practice for motion and certain force ideas. Folks seemed to do a nice job with that, but the open responses could have used more clarity, organization, detail and vocabulary for some questions. We'll practice this throughout the year, but start looking at your short answer questions and homework questions with an eye towards how this question would score if someone was grading it for your MCAS. Tomorrow is test day and on Thursday, we'll get deeper into the ideas of forces.

Honors Physics had more practice with working with forces and force diagrams. A good sketch, with all forces identified and labeled is a great help in solving these problems. Sometimes it is easiest to work backwards with these situations. Writing down what you are asked to determine (acceleration, net force, coefficient of friction, etc.) can start you thinking about what you directly need to solve for that variable (and there may be more than one possible pathway that you'll pare down to one as you evaluate the information), then what do you need to solve for the things to solve for that, etc. Tomorrow's lab will give you a better idea about the conceptual nature of friction and the coefficient of friction and we'll take Thursday to review the chapter ideas and tonight's homework. Test of Friday, so be prepared. I'll get a couple of videos up tomorrow for working with forces that might help you with the problems due on Thursday.

Friction

Physics A and B enjoyed their Chapter 3 exam, but B Block got to take advantage of the scheduled long block and use the second half of the period to conduct a lab investigation on friction. Students investigated kinetic friction and how it was affected by the surface texture of the materials in question. Attention then turned to the coefficient of friction, which gives some quantitative measure as to how surface textures influence friction. We'll go over the lab tomorrow before heading (with A Block) into forces and Newton's laws of motion.

Introductory Physics reviewed for their Chapter 10 test, which is scheduled for Wednesday. We went over the weekend's homework before walking page through page through the chapter, highlighting information and skills necessary for Wednesday and pointing out things we covered in class that are NOT in the chapter. Folks were sent home with two packets of review material made up of questions from old MCAS exams. We'll go over them in class tomorrow and address any last-minute issues for Wednesdays assessment.

Honors Physics reviewed the concept of the normal force (F_N) and added in how to calculate the normal force when objects are on inclines and/or are being acted on by an applied force. Remember that the normal force generated by a surface will be equal and opposite to the magnitude of the force pressing down on it. If you are lifting up or pressing down on an object, that force will subtract or add to the object's weight (or component of the object's weight) and influence the size of the resulting normal force. We then linked normal force to friction. Static and kinetic friction were contrasted and will be the subject of Wednesday's lab. We looked at the factors that promoted frictional resistance and how the coefficient of friction and normal force were used to calculate the size of the frictional force an object experiences on or moving across a surface. We'll practice more with this tomorrow, along with how friction and the normal force factor into calculating the net force acting on a object and the resulting acceleration.

I Do NOT Want Diaper Duty

Friday's Fun and Test Review

Physics A and B spent Friday reviewing for Monday's exam on 2-dimensional motion and vectors. Here are two videos to help you prepare for that test, especially if you were absent on Friday. The first is a walk through the chapter and the second takes on three problem types that will show up on the exam: non-perpendicular vectors, horizontally-launched projectiles and projectiles launched at an angle...

Honors Physics reviewed their Chapter 3 exams and Newton's laws of motion before continuing on with specific forces. We covered weight on Thursday and connected that idea with the new topic of the normal force (F_N). As long as an object is on a horizontal surface and no one is pushing or pulling on it at an angle, the weight of the object is equal and opposite to the normal force provided by the surface. If the object is on an incline, only a component of the object's weight (mgcosΘ)is equal and opposite to the normal force. We'll look at how applied forces impact the normal force on Monday, as well as start a discussion about friction.

Introductory Physics worked with friction on Friday. We defined friction, contrasted static and kinetic friction and looked at examples of sliding, rolling and fluid friction. Make sure you are clear on the definition of all those terms and the reasons why some forms of friction are greater/lesser in magnitude than other forms. We'll look at this again tomorrow, review the chapter on Tuesday and have our Chapter 10 exam on Wednesday.

Forces

Introductory Physics took time to review yesterday's lab that focused on the topic of friction. We'll add a number of details to our discussion about friction during tomorrow's class, but the information we went over today should be enough to help you interpret your data and write up your lab. We postponed the due date for that from tomorrow to Monday, so you should have plenty of time to craft a good conclusion section, including any research time you might choose to use to enhance that section of your lab write up.

Honors Physics reviewed their work on Newton's 1^st and 2^nd laws of motion before tackling the last sibling in that series of triplets - Newton's 3^rd law of motion. This one sometimes gives people a little difficulty, so be clear that you understand that forces occur in pairs. Each member of the pair is equal in magnitude, but opposite in direction to the other. This does not mean, in any way, that the accelerations of the interacting objects will be equal and opposite. The accelerations will be based on the object's inertia, measured by their masses. So, if a mosquito hits a car's windshield, the mosquito and the windshield both experience the same magnitude of force. However, the mosquito will have a much larger acceleration due to the smaller inertia. Newton's 3^rd works with contact forces as well as with field forces such as gravity. In our discussion of weight (F_g), we used the pull of gravity on objects to show how both objects are influenced by the shared size of a pull, but how their resulting behaviors differ. Tomorrow, we'll start to look at the remaining of what your book calls "Everyday Forces," - the normal force (F_N) and friction (F_k,s).

Physics A and B reviewed their work with projectiles launched at an angle and took more practice with that topic during the class period. We'll have a general review for this chapter in class tomorrow to prepare for Monday's exam, so come with questions!

Back in the Saddle

After the extended weekend (with a teacher professional development day tossed in for good measure), folks were raring to pick up where they left off on Friday...

Physics A and B reviewed their work with horizontally-launched projectiles before launching into projectiles launched at an angle. We'll concentrate on projectiles for which the launch and landing heights are equal to facilitate problem solving. Remember to break your initial launch velocity into x- and y-components and use these components in your kinematics formulas. Keep in mind that the velocity in the x-direction is constant, the acceleration in the y-direction is -9.81 m/s², the velocity in the y-direction at the maximum height is 0 m/s and that the trajectory of the projectile will be a symmetrical parabola. You should be able to solve for horizontal range (Δx), maximum height (Δy_max) and total time in the air. We worked a sample problem in class today and there are a couple of videos posted a few days ago that you can watch to see other examples. We'll go over the homework tomorrow and if more practice is needed, we have time to do just that. Review time on Friday and exam on Monday - be prepared!

Introductory Physics engaged in a lab investigation that had people exploring the concept of friction. The impact of surface texture, surface area and mass on friction was evaluated and data was collected to let folks calculate the coefficient of kinetic friction (μ_k). That concept isn't discussed in your books, so we'll take time in class tomorrow to provide some background information on this and other concepts associated with the lab. The write up isn't due until Friday, so you'll have time to incorporate these ideas into your work.

Honors Physics built on their work with force and F_net to discuss Newton's 1^st and 2^nd laws of motion. Add the new vocabulary of inertia, equilibrium and equilibriant to your terminology suitcase. Also, make sure you are very clear, conceptually, on what those first two laws of motion have to say in terms of the impact of force on motion. Be able to, also, solve problems using Newton's 2^nd law of motion. You may have to do some work to calculate the net force first, but it is just familiar old vector work, so don't be nervous about jumping right in. We'll go over the homework items tomorrow before taking a look at Newton's 3^rdlaw of motion.

Forces and Motion

Honors Physics and Introductory Physics jumped into the arena of forces yesterday, with a look at the nature of forces, the ability to combine force vectors to find net force and the use of free-body diagrams to analyze the forces acting on an object. Honors Physics took a harder look at calculating net force and those folks should be able to combine any and any number of force vectors to determine F_net. We'll look at how to use that to assess an object's acceleration next week. For Introductory Physics, be able to calculate F_net for forces that are in the same direction or opposite directions and be sure you are clear about the distinction between balanced and unbalanced forces. For both groups, don't lose sight of the meaning of F_net = 0 N. It means no net force, balanced forces, no acceleration and object moves with constant velocity. Also for both groups, remember that only forces that act directly on an object are included in free-body diagrams, not forces that the object applies to other objects. Next week, Introductory Physics takes a look at friction and Honors Physics steps into Newton's laws of motion.

Physics A and B both worked on evaluating horizontally-launched projectiles. For horizontally-launched projectiles, remember that some information important for problems solving won't be directly stated in the problem. The fact that the initial velocity in the y-direction is 0 m/s and the velocity in the x-direction is constant (and the stated launch velocity), won't be spelled out for you. Also, remember that accelration in the y-direction is -9.81 m/s² and is 0 m/s² in the x-direction. The time you calculate for the object to hit the landing point is the same time as for the ball to cover the horizontal range. You need all that information in your pocket, along with any explicit information in order to work these problems. We'll go over the homework items on Wednesday when we return from the extra-long weekend and then add a layer of complexity by tackling projectiles launched at an angle.

Rain

A whole summer of nothing and now it won't stop raining. And I can't stay home, curled up with popcorn and a movie, to enjoy it...

Physics A and B reviewed their work with non-perpendicular vectors and it was decided in both classes that a little more practice was necessary before moving on. So, we worked through more examples and we'll wait to take on horizontal projectiles until tomorrow.

Introductory Physics also had an additional practice day. The graphing portion of yesterday's quiz indicated that some folks still needed a little work in that area, so we worked on a problem that involved graphing and a bit of the ol' kinematics formulas. We'll check over that tomorrow to make sure everyone's feeling good about graphing before taking on forces.

Honors Physics took their postponed Chapter 3 exam. We wound up using most of the long block, but that's not a problem in the grand scheme of the year's schedule. Tomorrow, we dive into forces and Newton's laws of motion.

A Day of Variety

Physics B reviewed their projectile motion lab and their work on resolving vectors before plunging headlong into the topic of non-perpendicular vectors. Make sure to carefully follow the steps we listed in class and pay attention to the sign of each vector. The video posted yesterday will give you a review of this process if you need a little reminding. Tomorrow, we'll go over these problems and then take a deeper look into the properties of horizontally-launched projectiles.

Physics A investigated the motion of a horizontally-launched projectile during today's long block. With a few measurements, folks were able to calculate a target distance and land a ball bearing right in a plastic cup. Then, the task was to calculate and set a launch velocity to hit a given target distance. We'll go over the lab tomorrow before we review our work on non-perpendicular vectors. Then, we'll use the lab to highlight the general discussion about properties of horizontally-launched projectiles. If you didn't get a chance to copy the Summary of Results and Conclusion ideas from the board, check out yesterday's post...

Introductory Physics took their graphing motion and kinematics quiz. Overall, the kinematics portion wasn't bad, but the graphing still needs work. That's fine...we have time...

Honors Physics had their test postponed until tomorrow. With 5 students being dismissed 25 minutes early and another few being absent, giving the exam today wasn't perhaps the best use of time. So, students had more review time and we'll work on the exam tomorrow in class. Time permitting, we'll conduct some investigation associated with forces, but we'll have to see how the period plays out...

Non-Perpendicular Vectors

Projectiles

Physics A took time to discuss and practice techniques for working with non-perpendicular vectors. When vectors don't make a nice right triangle on their own, we must take a more complex approach to combining them. Remember the steps:

1. Sketch the situation, double-checking the direction of each vector.
2. Resolve each vector into x- and y-components, paying close attention to signs.
3. Sum all of the x-components and y-components for the vectors.
4. Make a right triangle with the Σx and Σy values.
5. Solve for the resultant, remembering both magnitude and direction.

I'll try and post a video for working with non-perpendicular vectors later today. We'll go over your homework problems on Thursday, so make sure you see me if you need extra help. Tomorrow - a lab on projectile motion. Physics B worked on the projectile motion lab in class today, calculating the landing point of a horizontally-launched projectile and testing how accurate was their prediction/calculation. Given a measured launch velocity and other bits of information, all groups hit their targets on the first try. Some groups got to engage in the Extension, where a target distance was set and the launch velocity had to be calculated (and then established). We'll go over projectile motion in more detail towards the end of the week, but remember our discussion at the start of class and use the following guidelines for helping you with your lab write up:

Summary of Results:

Main experiment - Given a table height of _______ and a launch velocity of _______, we predicted a landing distance of _______ and hit/failed to hit the target.

Extension - Given a target distance of _______ and a table height of ________, we predicted a launch speed of _______ and hit/failed to hit the target. Conclusion Ideas:

Conclusion Ideas:

• What is projectile motion?
• Why can we factor out air resistance for the ball bearing's motion?
• How did you make your predictions?
• What assumptions did you make?
• What information, measured or not, did you use?
• Why was v_x constant?
• Why did the trajectory of the motion look like half a parabola?

Introductory Physics reviewed their kinematics problems and we worked some extra for additional practice as a class. A 5-question quiz tomorrow will check both your ability to interpret/create graphs of motion and your skills with kinematics. Then, it is on to an introduction to how forces impact motion (covered in more detail in the next chapter).

Honors Physics reviewed their work on projectiles launched at an angle and also had a general review for tomorrow's exam. On Thursday, we move on to forces and the Newton's Laws of Motion.

The Math of Motion

Introductory Physics had the whole period set aside to practice working with the kinematics formulas on their MCAS formula sheet. As we go through the year, you'll see why organizing your work is very important for success. List your information (variable, value, unit, direction) and don't hesitate to actually write down the variable for which you'll be solving. Read the problem again for any information given in words (at rest = v_i = 0 m/s, for example) and add that to your list. Look at your formula sheet and see if there is any equation that directly lets you use your list of information to solve for your desired variable. Sometimes you get lucky, other times you don't. If there's not one equation, look for an equation that will use your current information to add more to the information list. That may crack open a formula that let's you get to the desired end point. At this level, it is not about being given numbers and just plugging them into an equation; at this level, you are expected to be able to plan an attack with what you're given to conquer the problem, regardless of how many steps you need to get to that victory. We'll go over the problems tomorrow and take more practice if it is needed. If not - on with more motion!

Physics A and B moved into the topic of vector resolution today. On Friday, we showed how two perpendicular vectors could be combined into a resultant that had both magnitude and direction; today we turned around and went backwards. Vector resolution takes a single vector with magnitude and direction and breaks it apart into two perpendicular components. We introduced the sine and cosine functions to solve for horizontal and vertical components of vectors and the practice you did with this technique, along with Friday's vector combination practice, will help you solve problems throughout the year. Tomorrow, we combine the two techniques to tackle the slightly more complex situation of non-perpendicular vectors.

Honors Physics had a great time since I wasn't in class, though why I found the remnants of balloons and llama fur in my room when I returned shall happily remain a mystery. Folks got more practice with projectiles launched at an angle and these problems were a bit more complex than the ones we worked last week. If you get stuck, check the online solutions or go back and watch yesterday's videos. We'll go over these problems tomorrow as part of our general review for Wednesday's exam.

Projectiles Launched at an Angle (2)

Projectiles Launched at an Angle

Phryday!

And a welcome Phryday it is...

Physics A and B practiced using some math techniques to combine vector quantities. Yesterday's work with the graphical method of combining vectors went well, but it was pretty easy to pick out the downsides of that path - need for equipment and problems with accuracy. As long as the vectors being combined are perpendicular to each other, slapping together a quick right triangle and using the Pythagorean Theorem to get the magnitude of the resultant and the tangent function to find the directional angle, works much faster and far more accurately than the graphical method. We practiced vector combination in class and Monday will bring the idea of vector resolution - taking one vector and breaking it down into its x- and y-components.

Honors Physics moved from horizontally-launched projectiles to projectiles launched at an angle. The same formulas are in play, but the launch velocity now has both a horizontal and vertical component. Make sure to break that initial velocity apart and use only the y-component for vertical work and the x-component for horizontal work. Also, keep in mind the hints and tips I gave you in class and that you used for the classwork problem. If I get a chance, I'll put up a video on working with projectiles launched at an angle and you'll get more practice with this problem type on Monday.

Introductory Physics reviewed the basics of creating and interpreting graphs of motion, building off of yesterday's lab. You should be able to create a position/time or velocity/time graph of motion described in words and evaluate a position/time or velocity/time graph for the motion it is describing. Calculating the velocity from a position/time graph and acceleration from an velocity/time graph (including sign or direction) should also be a skill in your toolbox. We then talked about how the kinematics on the MCAS formula sheet can be used to make predictions about motion and started practicing making calculations using these formulas. You'll get a lot more practice with this on Monday.

Have a great weekend!

Feeling the Motion

Introductory Physics spent the long block working on their Graph Matching lab. Folks had to interact with prepared graphs of motion and enact the motion they described. A motion detector tracked their movements and plotted them against the prepared plot to see how the people did matching their motions to the graph. Both position/time and velocity/time graphs were enacted and students also had the opportunity to create their own graphs and have groupmates try and match their directions. We'll go over these labs tomorrow and make sure that everyone is comfortable interpreting basic graphs of motion.

Physics A and B started their work with vectors today by examining the nature of vectors and the graphical method of vector addition. Vectors will be an important part of this year's work, so a firm hand dealing with vector topics is necessary for success in the class. We practiced how to create vector diagrams to scale using rulers and protractors and determining the resultant through direct measurement. Tomorrow, we'll start to add mathematical tools to combining vectors. If folks aren't up-to-date with the Pythagorean Theorem and the use of the tangent function, you'll get a thorough review tomorrow.

Honors Physics spent extra time yesterday working with non-perpendicular vectors, so today was horizontal projectile day. We looked at properties of projectile motion, in general, and worked with the math of evaluating horizontally-launched projectiles. Tomorrow, we'll add projectiles launched at an angle to our list of skills and then move to the area of relative motion. We've actually talked about that a lot, but this time we'll work with it mathematically with vectors.