Torquin' Through Monday

Honors Physics completed their discussion of simple machines. We reviewed the types of simple machines, described how they functioned to make work easier and the two formulas for mechanical advantage. Added in the concept of efficiency emphasized the connection between the action of many of the simple machines and the concepts we've been covering in the rotational motion unit. Tomorrow, a lab that takes us back to centripetal force and tangential velocity. Wednesday, review and Thursday will be exam day.

Physics B conducted a lab investigation on rotational equilibrium. Setting up balanced torques for a variety of masses demonstrated clearly that force (weight) was not the only player in the game. Lever arm is critically important and rotational equilibrium is dependent not on balanced forces but on balanced torques. Tomorrow, we'll discuss the lab in more detail before continuing on with our discussion of rotational inertia and angular momentum.

Physics F spent time with rotational inertia and applied that idea to rolling. How easily an object rotates or rolls depends on its moment of inertia, and that depends on the object's mass and the distribution of that mass around the rotational axis. For single objects, there are often several axes around rotation can occur, but it is easier for some than for others. We looked at some moment of inertia formulas for simple shapes and it became clear why for a hoop and a ball, with identical masses and radii, the ball would always win a race when propelled by the same force - smaller moment of inertia = easier rotation.

Physical Science took time to discuss laboratory write ups. There's been problems in that area, so with the lab we just completed as a guinea pig, we looked at what each section of the lab write up should contain and what needed to be done to the current labs to bring them up to code. Work on your rewrites tonight and let's see how things look tomorrow.

Homework

Honors Physics: 8.4 Section Review and p. 308 #39 - 43
Physics B: None
Physics F: p.165, 166 in packet #7-13 and 27-30
Physical Science: Rewrite lab write ups for simple machines labs

They See Me Rollin'

They calculate my moment of inertia...

Honors Physics went over their work on angular momentum and angular kinetic energy before moving on to simple machines. In grade 9, we lumped simple machines in with the work and energy chapter and that's fine. Both arenas, rotational motion and work are good ways to evaluate machines. We defined machines and began to look at how they functioned to make work easier. Actual and ideal mechanical advantage were contrasted and we will pick up with the families of machines and efficiency on Monday.

Physics B and F went over their torque work before beginning a discussion of rotational inertia. Objects do resist changes in rotation, but mass is not the only player. The distribution of mass is also important. Clustering mass around the rotational axis produces a lower rotational inertia than placing the mass at a distance from the axis. We'll build on this next week. On Monday, B's long block, look forward to a lab dealing with rotational equilibrium.

Physical Science got time in class to work on test corrections. Students can earn up to a maximum of 1/3 the points they missed back on their score. Next week, talking about lab write ups and continuing on with work and power.

Homework

Honors Physics, Physics B and F: None
Physical Science: Complete test corrections (if you get completely stuck on one, remember to ask me in class on Monday)

Circular Motion Continues

Honors Physics took time to review and refresh their problem solving skills for rotational equilibrim before moving on to other properties of rotational motion - angular momentum, Newton's 2nd law applied to rotational motion and rotational kinetic energy. The concepts are familiar, they are now simply applied to rotating bodies. For problem solving, here's a hint (especially for conservation of energy problems): ω = v_t/r...

Physics B and F reviewed their torque homework and spent time working with the idea of rotational equilibrium. The problem set for homework will make you think, so here's your hint: Sometimes you need to look at both conditions for equilibrium to be able to solve a problem.

Physical Science completed their simple machines lab. Little problem following directions for the lever piece, but everyone finally pulled together a good set of data. Get the writeups completed (along with your examples of the three classes of levers) for tomorrow so that we can use the information to illustrate our discussion of work and power.

Homework

Honors Physics: 8C #1, 2; 8D #1, 3; 8E #1, 2
Physics B: Torque practice problems packet
Physics F: Ancillary packet p. 165-166 #1-4, 21-23 and Torque practice problems packet
Physical Science: Complete lab write up

Rotational Motion

Honors Physics continued on today with their study of rotational dynamics with an overview of moment of inertia and rotational equilibrium. Moment of inertia stands in for mass in rotational systems - mass distribution is very important for extended objects and their overall motion. For equilibrium, we had to add on a new condition - an object in complete equilibrium must be subject to both zero net force and zero net torque. So, an object can be in translational equilibrium, rotational equilibrium, both or neither. The problem set you have tonight assumes complete equilibrium and uses that scenario to have you determine the magnitude of forces. The solutions are on Edline and here's another link for you to use.

Physics B and Physics F completed their circular motion labs. No one got a black eye from getting whacked with a rubber stopper, so it was a great success. We'll talk about the lab tomorrow before heading into rotational dynamics.

Physical Science completed their two simple machine experiments. The inclined plane reduces your effort force by providing more distance through which to put the force. The first and second class levers do the same thing. Third class levers make you put in more force than the machine gives out, but that is good if you need to do some delicate work (like with computer circuitry) or if you need an increase of distance, instead. Tomorrow, we'll use the labs to help introduce our unit on work, power and simple machines.

Homework

Honors Physics - Practice 8B #2, 3 and 4
Physics B and F: Complete Centripetal Force and Speed lab write up
Physical Science: Complete Inclined Plane and Levers lab write up

More Monday, No Turkey

Hopefully, everyone had a nice Thanksgiving vacation and got a chance to rest and relax. Now, back to work...

Honors Physics began their chapter on rotational dynamics with a discussion of torque and center of mass. Torque acts as a force analogue in rotational motion - forces with the same magnitude to not produce the same rotation if applied to different locations or at different angles. Net torque, also, is analogous to net force: a nonzero net torque produces rotational acceleration, zero net torque keeps the object in equilibrium. Torques is going to come again soon when we begin to look at Newton's laws from a rotational perspective. Attention then turned to center of mass and its role in rotation. The center of can be thought of as the natural axis of rotation for an object, since it is around this point an object will spin when acting only under the force of gravity. We discussed examples of this and also the role of center of mass/gravity (not the same thing, but close enough for our purposes) plays in stability. Tomorrow - moment of inertia!

Physics B began an investigation on centripetal force, rotational radius and rotational speed. Students maintained a constant radius for a stopper being whirled on a string and determined how the centripetal force affected the rotational speed required to maintain this radius. We'll finish up the lab tomorrow before turning, on Wednesday, towards rotational mechanics.

Physics F launched into a discussion of rotational motion by examining the descriptors of rotational motion and linking them to the concept of centripetal force. Many people use the term centrifugal force in this arena and time was taken to clear up that misconception. We also added in a little on center of gravity. Tomorrow, a lab that looks at centripetal force and angular speed for a system demonstrating rotational motion.

Physical Science took their force and momentum exam and then began the first of two lab investigations into the area of work and simple machines. The inclined plane was the focus of this lab and we'll continue with it and add in levers tomorrow.

Homework

Honors Physics: Practice 8A and the 8.1 Section Review
Physics B and F: None
Physical Science: 12.1 Section Review

Phryday!

Honors Physics spent some time discussing the idea of centripetal force. Remember, that term is really a job description. Different forces perform that role, depending on the the situation. The direction of the force matches the direction of centripetal acceleration - towards the center of the circle/axis of rotation. Time was then given for students to practice solving problems for rotational motion. We'll go over those on Monday before turning attention to gravity. We've looked at acceleration due to gravity and verified the value in lab. Now, how do we calculate how big is the force that produced that acceleration?

Physics B watched a Mythbusters segment that introduced the upcoming unit on circular motion and also reinforced concepts for force, momentum and pressure. We'll start up with circular motion on Monday and Tuesday's lab will allow you to observe the effects of mass and rotational radius on the magnitude of centripetal force. Physics F endured their work and energy exam, so not much to report on that front.

Physical Science concluded their MCAS review for force, laws of motion and momentum. We'll review these topics and upcoming ones as we go along through the year and take last year's full test as a status check before the real test in June.

Homework:

Honors Physics: 7E #1, 2; 7F #1, 3; 7G #1, 3, 5; 7H #1, 4; p. 271 #47
Physics B: Complete Mythbusters discussion questions:

1. List 5 things that move with circular motion. Explain how they are able to move in a circle - why don't they just move in a straight line (Hint: think about force).


2. Do you enjoy rides that move with circular motion. Why or why not?

Physics F: None
Physical Science: None

Child's Play

Ok, so there's a new link on the sidebar and it asks you to donate. If you don't know about Child's Play charity, click on the logo and read what these people do. Powered by the gamer community, the proceeds and items go help sick kids. I donate every year, to the Children's Hospital in Boston, through their Amazon.com Wish List and also choose another hospital, from my home state of Louisiana or out of the country to contribute. Last year, I sent a sweet Xbox 360 pack to two hospitals to let kids stuck in hospital beds forget about their troubles for a little bit while playing whatever little kids play - Viva Pinata or Barbie's Horse Adventures or something. Regardless, its a good deed and something that shows that gamers aren't the crazed maniacs that the press sometimes likes to portray. Last year, they took in over 1.5 million in cash and toys...if you have a few extra bucks and you consider yourself part of the gaming community, consider donating to help some kid who might be spending the holidays in a hospital rather that at home with their folks. Gamers rock the house and its time the world caught on to that fact. Ok, rant and propaganda time over with. See everyone tomorrow...

PTCR2

Round 2 of parent-teacher conferences...students get a half-day and we get a long lunch...everyone gets a little something nice...

Honors Physics went over their momentum exams before reviewing last nights homework for kinematics of angular motion. Attention then turned to exploring the relationship between tangential motion and rotational motion for objects and added a new player to the game - centripetal acceleration. Tomorrow, we'll look at forces that can promote circular motion and see why they all get lumped into a single category - centripetal force.

Physics B took their work and energy exam. Tomorrow, we take up rotational motion and keep that track for the next couple of chapters.

Physics F and Physical Science didn't meet due to the half-day schedule

Homework

None for anyone!

PTCR1

Parent-Teacher Conferences tonight and tomorrow, so make sure to be very polite at home to buffer "the talk" you'll get when your parents come home afterward...

Honors Physics embarked on a study of rotational motion. The nice thing for this first piece is that the topics are familiar - displacement, speed, acceleration, kinematics - they just have a slightly different twist. Once you orient yourself as to how to define angular displacement, the rest is easy. Tomorrow, we'll look at how angular motion and linear motion affect each other and also add in a third acceleration value - centripetal acceleration - which is what promotes the circular motion to begin with.

Physics B reviewed their Machines and Efficiency math packet and addressed any final issues before tomorrow's exam. Physics F, on the other hand, conducted two lab investigations centering around conservation of energy. The motion of a basketball tossed into the air was used to corroborate conservation of energy and conversion of energy between kinetic and gravitational potential forms. A second experiment with a mass-spring system focused on kinetic and elastic potential energy. Some groups still have a bit to do on that last one, so there will be time provided in class on Monday to complete the work.

Physical Science reviewed their MCAS practice material for forces, laws of motion and momentum until they were called down for Peer Mentors. We'll continue to review the packet on Friday and start a general review of the material for this unit looking towards Tuesday for the unit exam.

Homework

Honors Physics: 7.1 Section Review and Practice 7D
Physics B and F: None
Physical Science: None

Momentum, Energy and Stuff

Honors Physics endured their momentum exams and will start a new unit tomorrow - rotational motion. Everything we've talked about so far has occurred in a linear model, now, we add in what happens when something rotates or revolves. Remember to set those calculators to work with angles in radians and light a small candle to the saint of the unit circle, because we're playing in that pool for the next two chapters...

Physics B and F worked on math practice for work, power, energy and simple machines. B block will go over these problems tomorrow and tie up any loose ends before Thursday's exam. F Block will go over these over the next two days, as time permits, while also working through a conservation of energy lab and having no class period on Thursday due to parent-teacher conferences.

Physical Science worked practice problems for conservation of momentum, which we went over in class and then began MCAS practice for forces, laws of motion and momentum. We'll go over that material tomorrow in class and talk about strategies for the MCAS exam that is looming in June.

Homework

Honors Physics: Complete the lab write up for yesterday's investigation
Physics B: Complete Machines and Efficiency math packet
Physics F: Have Machines and Efficiency math packet completed by Friday
Physical Science: Complete MCAS review packet

Momentum

Honors Physics conducted a lab investigation on momentum and kinetic energy conservation for different types of collisions. Students modeled elastic, perfectly inelastic and inelastic collisions and tracked momentum and energy changes for each type. The lab write up is due Wednesday since tomorrow is test day!

Physics B and F reviewed material for the momentum exam, which is scheduled for Thursday for B block and Friday for F block. Time was also taken to review the lab unit on simple machines. Not surprisingly, the machines behaved as they should - multiplying force or distance (but not both) and demonstrating IMA values greater than AMA values. tomorrow, math practice!

Physical Science reviewed conservation of momentum and worked some practice problems for the topic. Tomorrow, more practice and then practice on force and momentum problems for MCAS.

Homework

Honors Physics: Prepare for exam. Lab write up due on Wednesday
Physics B and F, Physical Science: None

Machines

Physics B and F began their lab unit on machines. The inclined plane, all three classes of simple levers and various pulley configurations will be tested for efficiency, actual mechanical advantage and ideal mechanical advantage. Students will also get a good chance to really see how these machines function to make work easier. Pretty much every group finished or nearly finished the inclined plane portion, so levers should be on the docket tomorrow. For inclined planes, it was quite clear that the effort force was less than the output force (weight of the load), but amount of work input was greater than the work output. Such is the cost of using a machine...

Honors Physics completed their discussion of impulse and momentum and we took time to review the lab and go over the impulse-momentum homework problems. Attention then turned to one of the biggies in physics - the law of conservation of momentum. The total momentum of a system remains constant in the absence of outside forces. Whatever momentum is lost by one object, that momentum is gained by someone else and vice versa. We discussed how conservation of momentum is mandated by Newton's 3^rd Law of Motion, which can be extended to say that the impulse experienced by two objects in a collision are equal in magnitude, but opposite in direction. We'll look at momentum conservation more tomorrow, before moving on to types of collisions.

Physical Science went over their impulse-momentum problems and it was clear that a little more work was needed. So, students have to create their own worksheet for momentum and impulse-momentum problems, script an answer key and be prepared to share their worksheet with others tomorrow in class.

Homework

Honors Physics: Practice 6D and the 6.2 Section Review #2, 4
Physics B and F: None
Physical Science: Self-created momentum and impulse-momentum worksheet and answer key

The Funny Thing Is...

...young Wookies are called "pups."

Monday

That single word is enough to cripple the spirits of any individual...

Honors Physics went over their work and energy exams and then launched into a discussion of impulse and momentum. FΔt = Δp describes the action of an impulse on an object's momentum and also nicely spotlights the role of time. Newton's 2^nd Law of Motion sometimes doesn't emphasize the role of time, as it gets hidden in the acceleration variable. But duration of force application is as important to changing an object's momentum as the force's magnitude. We discussed the idea of follow-through in sports and will highlight other examples of the role of time in tomorrow's class. Have your labs and 5A, 5B ready for tomorrow. We'll discuss the lab (which we already started doing today) and review those problems before moving on to conservation of momentum.

Physics B and F reviewed the six simple machines and how they function to make work easier. We then introduced the ideas of mechanical advantage and efficiency, which will be targeted heavily in the lab unit that we begin tomorrow. We'll look at inclined planes, all three classes of levers and pulleys (simple, movable and pulley-systems.) You'll calculate IMA and measure AMA to evaluate the machine's efficiency and also get a better look at how these machines manipulate force or distance to make work easier.

Physical Science went over their lab investigations in class and used them as an example to reintroduce the Impulse-Momentum theorem. We took time to review this idea before plunging headlong into some examples of this is mathematically applied. After we went over a couple of practice problems, students were given a sheet with additional samples to work. We'll go over these in class tomorrow before turning attention to conservation of momentum.

Homework

Honors Physics: None
Physics B and F: Complete Work and Energy review packets
Physical Science: Complete Impulse-Momentum practice problems

Honors Physics - This One's For You

Rain, Rain Go Away

Today's rain has pretty much set the stage for people's mood and energy level. Tomorrow, likely more of the same.

Honors Physics completed their impulse-momentum lab, which we will discuss tomorrow. The unit that the lab introduced, momentum and its conservation, builds on our work with forces, Newton's laws of motion and work to investigate another major physics concept. We'll tackle the impulse-momentum theorem, conservation of momentum and types of collisions before the unit is completed.

Physics B went over their Energy and Machines math packet before turning attention to the idea of machines. Yesterday's discussion of conservation of energy definitely applies to machines in that no machine can give you more work out that you put in. We began to look at the inclined plane family today and will continue with that and hit the lever family tomorrow. Then, we start a series of investigations with the simple machines. Physics F completed their material on the simple machines today and are ready to start lab work with conservation of energy and machines tomorrow.

Physical Science spent yesterday going over their momentum problems. Always remember to identify information, write down the formula and place information in the formula according to the variable it represents before just trying to punch numbers into the calculator. Also, you can never forget about those unit conversions. Today, students worked on a lab centering on momentum and how both mass and velocity affect an object's momentum. We'll discuss the lab tomorrow and start working some problems for the impulse-momentum theorem.

Homework

Honors Physics: Complete lab write up
Physics B and F: None
Physical Science: Complete lab write up

What Happens When You Spend All Day in the Patent Office

There Will Be Awesomeness

Shakespeare Goes Sci-fi in Michael Caine's Post-apocalyptic Henry5

Weak Monday

With the field trip today and a slew of general absences, classes were a little light on attendance. No matter, we'll catch people up tomorrow.

Honors Physics took their work and energy exam today and will leap into momentum on Wednesday with a lab on the impulse-momentum theorem. Interested people can read ahead in Chapter 6, but the lab does a good job on its own introducing the concept and letting you work with the math behind the idea.

Physics B, with a rocking total of 3 people, conducted two lab investigations, both of which targeted energy and its conservation. One lab looked at gravitational potential and kinetic energies and the second targeted kinetic and elastic potential energies. The lab nicely showed that regardless of how energy was divided up between the players, the total value remained constant. We'll go over the lab on Wednesday and take time to discuss kinetic and elastic potential energy in more depth.

Physics F discussed kinetic energy and elastic potential energy in class and got some practice with the problem solving for the various energy types and conservation of energy. We'll go over conservation of energy and review these problems in class tomorrow.

Physical Science went over their forces math quiz and were introduced to the concept of and formula for momentum. Remember not to confuse momentum with inertia - all mass has inertia, but only mass in motion has momentum. We'll go over the homework problems in class tomorrow before digger deeper into momentum and its conservation. The solutions to the homework problems can be found here.

Homework

Honors Physics: None
Physics B: Complete lab write up
Physics F: Complete Energy and Machines math packet
Physical Science: Complete Momentum math packet

Halloween

Kudos for everyone who wore a costume today to celebrate Sunday's spooky holiday. Everyone looked great!

Honors Physics reviewed their power homework before walking through the chapter as a general review for Monday's exam. On Wednesday, you'll conduct a lab investigation on the Impulse-Momentum Theorem, which we'll discuss in class on Thursday.

Physics B and F reviewed their work and power homework before stepping into the world of energy. Not all forms of energy are easily available to do work - chemical and nuclear, for example - but the ones that are will be the focus of this unit. We started with gravitational potential energy and described how position in a gravitational field and mass affect an object's PE_g. We'll add elastic potential energy and kinetic energy to the pot next week. On Monday, B Block will conduct a lab investigation that allows folks to see the various types of energy in action and focuses on the big-ticket item that is conservation of energy.

Physical Science took their forces math quiz before taking the tiniest of peeks at momentum. We'll discuss momentum in more detail on Monday and conduct a lab investigation on momentum on Thursday.

Homework

Honors Physics: Prepare for exam
Physics B and F: None
Physical Science: None

What's With the Weather?

This school year has started with the weirdest weather. Ever. That's all I have to say.

Honors Physics went over their work and energy homework problems before turning attention to power. Be very aware that power is the rate at which work is done or energy is converted, not the amount of each in question. We discussed a number of examples where the amount of work done by two machines was identical, although the power varied dramatically. We'll tidy up loose ends with power tomorrow before engaging in a general review in preparation for Monday's exam.

Physics B and F began their unit on work and energy. We defined work and discussed how force and distance play into the calculation of work. Positive and negative work examples were described and we then took time to look at the rate at which work is done - power. Be very clear about the scientific definitions of work and power and recognize examples of when work is being done by a force and when a force is not doing work on an object.

Physical Science had a discussion on Newton's 3^rd Law of Motion. Keep in mind that the "action" and "reaction" terms for N3 refer to the forces involved and not the responses of the objects after experiencing those forces. When two objects interact, two forces are simultaneously generated, equal in magnitude and opposite in direction, but we have to go back to N2 to figure out what acceleration the forces impart on the individual objects. Also, remember that these forces do not produce equilibrium. They do not represent an example of balanced forces - the forces act on different objects. Tomorrow, another forces math quiz before starting to take a look at momentum.

Homework

Honors Physics: Practice 5F and the section review on p. 189
Physics B and F: p. 119 of packet #1-5, 21-23 and p. 171 of textbook #1-4
Physical Science: Study for forces math quiz

Momentous Tuesday

Physics F conducted a lab investigation that allowed students to examine the effects of velocity and mass on an object's momentum. As predicted by the momentum formula (p = mv), increasing either variable increases momentum and by a predictable amount. Double one and momentum also doubles, etc. The write up for the lab is due on Thursday, because you have more important things to worry about tonight - tomorrow's momentum exam!

Physics B went over their momentum review sheet before conducting a general review of the chapter. Some people took extra problems to work that give you an idea of what types of problems you might see on the test. Starting on Thursday - Work and Energy!

Physics B and F - SOLUTIONS TO EXTRA MOMENTUM PROBLEMS AVAILABLE HERE!!!

Honors Physics built on last week's discussion of work and kinetic energy by adding gravitational potential energy and elastic potential energy to the fix. Both are energies of position and both represent a storehouse of energy available to do work. To get that energy stored up, work had to be done on the object (lifting it to a height, compressing/stretching an elastic material) and you can equate the amount of work done on the object the amount of energy stored. Release that energy, and that is how much the object can do. Tomorrow, we'll go over the lab and use it as an example as we discuss conservation of energy.

Physical Science went over their quizzes and then started work on another set of similar problems. Folks didn't do so well on this quiz, so more practice is indicated and there will be another quiz on the same three problem-solving areas on Friday.

Homework

Honors Physics: 5.1 and 5.2 Section Reviews
Physics B and F: Study for exam. Physics F should complete lab write up by Thursday
Physical Science: Complete Forces Review problems
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Charging Into A New Week

Honors Physics completed the conservation of energy labs that they began on Friday. A tossed ball demonstrated conservation of energy between kinetic and gravitational potential conversions and a mass-spring system did the same for kinetic and elastic potential energy. The total in the system remains the same, but the values for individual forms and types can, and do, change. We'll continue our energy discussion in class tomorrow and by Wednesday, should be ready to look at COE using your labs as as examples.

Physics B contrasted perfectly inelastic, inelastic and elastic collisions based on such factors as kinetic energy conservation, deformation of objects and momentum conservation. All conserve momentum, but other factors do vary between types of object interactions. Time was then provided for students to begin working on their review packet for Wednesday's exam.

Physics F went over their exam review packet and addressed any final questions about momentum. Tomorrow's lab should help to cement things prior to the exam on Wednesday.

Physical Science took a quiz for Newton's 2^nd Law of Motion, weight and gravity problems. We'll go over the quiz in class tomorrow. Then, a lab investigation was launched to look at air resistance. We discussed air resistance in class Friday, including how it varied with the mass, speed and shape of an object. Tomorrow, we'll go over the lab before moving on with projectile motion.

Homework

Honors Physics: Lab write up due Wednesday
Physics B: Complete momentum review packet
Physics F: None
Physical Science: Complete lab write up

The Secret is Finally Revealed

If You Don't Get It, You Won't Get It

It's Friday, I'm in Love

With trashy action flicks...Time for a Pitch Black/Chronicles of Riddick movie fest with some Mortal Kombat: Annihilation tossed in for good measure...

Honors Physics started a series of lab investigations concerning conservation of energy. The first examined energy changes in a tossed ball and demonstrated patterns of energy change between kinetic and gravitational potential energy. The second targets energy in simple harmonic motion and tracks kinetic and elastic potential energy conversions in a mass-spring system. We'll finish up the lab work on Monday, so the lab write up wont' be due until Tuesday. Also on Tuesday, we jump deeply into energy with a detailed look of the various forms and types.

Physics B discussed conservation of energy and used last week's lab unit as an example. Regardless of type of collision, total momentum before the interaction equals the total momentum after the interaction, but the same cannot be said for energy of motion (kinetic energy). We'll classify collisions based on their ability to conserve kinetic energy (and other factors) on Monday.

Physics F went over their homework questions/problems and were then given review work to start on in preparation for Wednesday's exam. We'll go over this information, do a general review of momentum and conduct one extra lab investigation before the test.

Physical Science reviewed the homework problems for Newton's 2^nd Law of Motion and weight before looking more closely at free-fall acceleration. We added in the force of air resistance, today and discussed its effects on falling objects. The concept of terminal velocity was introduced and explained and linked to the reason that, in the absence of a vacuum, more massive objects do hit the ground before less massive objects. We then began a look at projectile motion that we will continue on Tuesday. Monday finds students taking a short quiz on the math skills they've practiced so far for forces and then embarking on a lab investigation for air resistance.

Homework

Honors Physics: None
Physics B: p. 101 in Packet #14, 15, 28, 29
Physics F: Complete momentum review packet
Physical Science: Study for forces math quiz

Thrilling Thursday

Well, for Physics B, at least, who got to crash dynamics carts into 3-ring binders to study momentum. The role of velocity and mass in determining an object's momentum was investigated today. Both mass and velocity have a directly proportional relationship with momentum. Double either and the momentum is doubled, for example. The carts launched at highest velocity had the highest momentum and doubling the cart's mass doubled his momentum, for each velocity tested. We'll go over the lab tomorrow and begin a discussion of conservation of momentum. Did you think about the fact that, in lab today, that when the cart hit the binder, the binder gained momentum and the cart lost some? That's what we'll hit with tomorrow' discussion.

Physics F contrasted elastic, perfectly inelastic and inelastic collisions after reviewing the impulse and conservation of momentum homework. All collisions, in the absence of pesky things like friction and other outside forces demonstrate conservation of momentum (even when they occur in a 2-dimensional motion framework), but only the purely elastic ones also conserve kinetic energy. The questions/problems you have tonight will help disentangle collision types and give you practice making predictions based on the momentum of objects in a system.

Honors Physics reviewed their forces exam before launching into a discussion of work and kinetic energy. For work, remember that Work_netis based on the net force acting on an object, but we can evaluate the work provided by single forces, if necessary. Work, although considered a scalar value, is flavored positive or negative and make sure you can describe what positive or negative work means in terms of an object's motion and energy state. We also hit the work-kinetic energy theorem today and will broaden that idea when we discuss potential energy next week. Tomorrow, a lab centering on energy in two distinct systems - a ball in free fall and an oscillating spring - and how well energy is conserved in both.

Physical Science took one last look at the mathematical aspects of Newton's Law of Universal Gravitation before discussing free-fall acceleration and weight. Make sure you are very clear about the difference between mass and weight, and also that you don't confuse "g" with "G" in problem solving. Both values are given on the MCAS formula sheet and you need to know which one to use in a given situation. Tomorrow, we'll go over the homework problems for weight and Newton's 2^nd Law of Motion before expanding our discussion free-fall with an exploration of air resistance and terminal velocity.

Homework

Honors Physics: None, but a reading of the energy bits of this chapter will make the lab activity tomorrow easier to understand
Physics B: Complete lab write up for the Impulse-Momentum work and today's Momentum lab
Physics F: Complete p. 100-101 of ancillary packet #16-22, 27
Physical Science: Complete the Chapter 11 Chapter Review #22-29

More on Momentum

Physics B completed their impulse-momentum labs today and it was quickly evident that more elastic materials stretched their forces over long time intervals, delivering less of a force to the carts to which they were attached. If you were a passenger in that cart, that would mean you would experience the slowing down, stopping, changing direction and speeding up more gently than would a passenger in the cart attached to the less elastic material. We'll discuss the lab in class tomorrow, so you'll have the impulse-momentum lecture and lab discussion under your belt before you go to complete the lab write up. Tomorrow also finds folks conducting another lab, this one on how manipulating mass and velocity affect an on object's momentum.

Physics F had a discussion of conservation of momentum today. Momentum is conserved in interactions, when outside forces are lacking. When one object loses momentum, it is gained by the second object in the interaction. The resulting velocity change can be predicted using this principle. The transfer of momentum between objects was demonstrated and the special circumstance of conservation of momentum in stationary systems (cannon/cannon ball; gun/bullet). Tomorrow, we'll go over the homework questions before examining the types and properties of collisions.

Honors Physics took their forces and laws of motion exam and tomorrow finds students engaged in a discussion of work.

Physical Science took a step off the path to review the basic math skills of cross-multiplication and isolating variables in simple algebraic expressions. Students were also highly encouraged to practice with their calculators to become quick and efficient working common functions such as inputting values in scientific notation, squaring values and taking square-roots and working with multi-variable numerators and/or denominators when dealing with fractions. The MCAS exam allows you to use your own calculator, so it is very much to your benefit to become adept with it as soon as possible. Students were then given more time to work the gravitational forces problems and should complete those for homework.

Homework

Honors Physics: None
Physics B: None
Physics E: p. 100-101 of ancillary packet #2, 7, 12, 14, 15, 26
Physical Science: Complete gravitational forces worksheet problems

Gathering Momentum

Physics B started a two-day investigation on the Impulse-Momentum theorem, which states that an object's observed momentum change is the product of the net applied force and the duration of the force's application. We'll finish up the lab in class tomorrow and, as you begin thinking about your write up, reflect on what we discussed about impulse and momentum yesterday in class. You'll get your exams back tomorrow morning and test corrections will be due on Monday.

Physics F discussed their lab investigation and launched into a general discussion of momentum and impulse. Use today's discussion to help frame the conclusions section of your lab write up, which is due tomorrow. Tomorrow, we'll start looking at conservation of momentum, which comes about because of Newton's 3^rd Law of Motion. Test corrections are due on Monday, so make sure to get help from me, if needed, before then.

Honors Physics went over their review problems and had a general review for tomorrow's exam. Remember to have those problems with you to turn in before the test tomorrow. Starting Thursday, its off to Work!

Physical Science reviewed Newton's Law of Universal Gravitation and received a set of problems to work using this law. The start was rocky, so we'll take more time in class to work on them. The answers to that sheet are below, if you decide to try to make more headway tonight.

1. 5.0 x 10¹⁵ kg
2. 2.26 x 10⁴ kg
3. 80.6 kg
4. 52 m
5. 26,000 m or 26 km
6. 1.0 x 10^-2 N

Homework

Honors Physics: Prepare for exam
Physics B: None
Physics F: Complete lab write up
Physical Science: None

A Gathering of Forces

Honors Physics reviewed their friction homework problems before moving on to a specific type of friction - air resistance. We discussed the fact that the value for air resistance is not constant between surfaces, but varies with speed and the practical applications that had for engineering high-velocity vehicles and spacecraft. We also looked at how this variable nature of air resistance works to create an maximum limit to the speed of objects in free fall - terminal velocity - and how air resistance makes heavier objects hit the ground faster and at a higher velocity than lighter objects. We will go over the review homework problems tomorrow before engaging in a general review of the chapter in preparation for Wednesday's exam.

Physics began their discussion of momentum and impulse. Momentum is a quantity possessed by any object in motion, but by no object that is at rest. Make sure you are very clear about the difference between momentum and inertia. We then spent time discussing the impulse-momentum theorem and what implication it has for sports, martial arts and safety engineering. Tomorrow, we'll go over the homework questions and then start a lab investigation on the impulse-momentum theorem.

Physics F completed their investigation on the impulse-momentum theorem. Sure enough, the more elastic the band, the greater the time for the change of momentum to occur and the lower overall force on the cart. We'll go over the lab in more detail tomorrow as we begin our discussion of impulse and momentum.

Physical Science reviewed their Newton's 2^nd Law of Motion homework problems before starting their discussion of gravity. Gravity is a force that is generated by all matter, but the magnitude of the force acting on a second object depends on the mass of the objects involved and the distance between them. We looked at Newton's formula to determine the value for the gravitational attraction between objects and took time to practice with this formula in class. Tomorrow a tasty problem set working with gravity!

Homework

Honors Physics: Chapter 4 Chapter Review # 52, 55, 57
Physics B: p. 100 in ancillary reading packet #1-10, 19
Physics F: None
Physical Science: None

Tru Dat...

Phinally Phriday...

Wow, for a short week, it sure has been a long one...

Honors Physics reviewed their homework problem for normal force, net force and acceleration before pole-vaulting into friction. Static and kinetic friction were contrasted the the nature of the coefficient of friction was described. To work problems with friction, proper calculation of the normal force is required, which is why we spent additional time on that topic yesterday. We'll go over the work on Monday, have a brief discussion on air resistance and then begin the review process for Wednesday's exam.

Physics B and F took their Forces exam, but since F was long block, Physics F got to begin a lab on the Impulse-Momentum Theorem. We start discussing momentum in B Block on Monday and F Block will have time to complete their labs.

Physical Science reviewed their N-2 lab before reviewing their N-2 homework assignment from Wednesday. The lab nicely demonstrated that when applied force is held constant, increasing mass decreases acceleration and decreasing mass increases acceleration, in accordance with Newton's 2^nd Law of Motion. Students then received a series of practice problems for N-2, which snuck in good things like unit conversions and calculations of acceleration. The answers to those problems are provided below, but we will go over them in class on Monday, as well.

1. 2.76 x 10^-3 m/s²
2. -448 m/s²
3. 0.400 m/s²
4. -6.12 m/s²
5. 0.37 kg
6. 2.0 x 10⁴kg
7. 9.5 x 10⁴kg
8. a. 0.2 N b. 2 kg
9. 2.06 x 10⁴N
10. -1.86 x 10⁷N
11. -3.6 x 10⁵N
12. 1.7 x 10⁶N
13. 9.4 m/s²
14. 15 kg
15. 3.16 N
16. 0.532 m/s²
17. a. 6.41 x 10⁴kg b. 1.31 x 10³
18. a. -1.8 x 10³m/s²; 180 g b. 1.3 x 10⁵N

Homework

Honors Physics: 4C #2; 4D #1,4; 4.4 Section Review omit ALL of question 3 (note the change)
Physics B and F: None
Physical Science: Complete Newton's 2^nd Law of Motion problem sheet

It's All About Newton

Honors Physics spent time working with the idea of weight and the normal force. The weight of an object varies with location, though mass remains constant. We'll get into the force of gravity a little later to see why this variation in weight occurs. We then turned attention to calculating normal force for objects on horizontal surfaces (where it is equal and opposite to the object's weight) and on inclines (where it is equal and opposite to the component of the object's weight that is perpendicular to the incline). We also investigated how external forces acting on an object, such as pushes and pulls affect the normal force. Your homework problem has you work through these ideas and here are the answers if you want to check your work:

1. 342 N
2. 186 N
3. 2.3 m/s²

We'll go over this problem tomorrow before using the ideas we've been working on to tackle friction.

Physics B and F reviewed for their forces and laws of motion exam. Catch me tomorrow before school if you have any additional questions.

Physical Science started class by going over their graphing assignment. A graph of force (dependent) vs. mass (independent) produced a very nice straight line, corresponding to the tenets of N-2. The slope of the line represented the mass of the object. Students then investigated Newton's 2^nd Law of Motion with a lab activity. A constant force produced predictably diminishing accelerations as the mass of the object increased. N-2: acceleration is directly proportional to net force and inversely proportional to inertia (mass. We'll discuss the lab tomorrow and go over the N-2 homework questions/problems from yesterday.

Homework

Honors Physics: Complete normal force homework problem
Physics B and F: Prepare for exam
Physical Science: Complete lab write up

Wild Wednesday

Honors Physics spent the period kicking wooden blocks around on the floor to investigate kinetic friction. Actually, that was only a piece of the investigation, but it was the most entertaining to watch. Static and kinetic friction were both targeted in today's work. Static friction outclasses kinetic friction in terms of magnitude (given the same surfaces). You graphs demonstrated the force required to start the wood block moving was greater than the force required to keep the block moving at constant velocity. The peak force on your graph was indicative of the value for F_s,max, which must be overcome by an applied force for a object to be set in motion. Your value for F_k could be inferred from the graph segment indicating the block moving at constant velocity. Constant velocity indicates F_net = 0, so the applied force is being matched by the force of kinetic friction. Adding mass to your system increased the force of friction by increasing the normal force the block experienced. Part 3 of your investigation allowed you to look at position-time and velocity-time graphs for motion where kinetic friction acted as the net force. The acceleration value from the velocity-time graph (which was a constant value) and the block's mass allowed you to calculate the magnitude of the frictional force using N-2. We' start discussion everyday forces like friction and weight tomorrow. The lab isn't due until Friday, but we'll address any questions about the investigation tomorrow.

Physics B reviewed their Air Resistance lab and used the lab to illustrate various topics discussed in the chapter. We took some extra time to go back over Newton's 3^rd Law of Motion and students had some class time to begin working on their N-3 critical thinking questions. We'll go over these tomorrow before reviewing for Friday's exam.

Physics E shared answers for their N-3 critical thinking questions, then began the review process for Friday's exam. We went through the note packet, highlighting key topics and students are strongly encouraged to take some time tonight to go through the exam material and come with questions tomorrow to address in class.

Physical Science reviewed Newton's 1^st Law of Motion and then tackled Newton's 2^nd Law. Although many people view N-2 only as a formula F = ma or a = F/m, be very aware that N-2 actually says about the interaction of F_net and inertia to determine an object's change in motion. We took time to work a couple of practice problems with the N-2 formula before beginning a graphing assignment for Newton's 2^nd Law. Tomorrow, a lab investigation for N-2 is on the agenda.

Homework

Honors Physics: Lab write up due Friday
Physics B: p. 84-85 of the ancillary packet #19, 24, 25, 28, 29, 32, 36, 37
Physics F: Prepare for Friday's exam
Physical Science: Complete #33 on page 370 (due tomorrow) and the 11.1 Section Review (due Friday)

Back to the Salt Mine

Nice long weekend, but it had to end sometime...

Honors Physics used Thursday's lab activity to illustrate facets of Newton's 3^rd Law of Motion. Forces are generated at the moment of contact, both forces arise simultaneously, the magnitudes are equal, but the directions are opposite, etc. Remember that N-3 only refers to magnitude and size of forces, not the responses of the objects in the interaction. We have to go back to N-2 to figure that out. Also, the action-reaction forces are not responsible for equilibrium - they act on different objects. Our next step on the Force trail will be an examination of specific forces such as weight, the normal force and friction. Tomorrow's lab will focus on static and kinetic friction and the determination of the coefficient of friction between two surfaces.

Physics B discussed their N-2 and N-3 labs, then got another opportunity to investigate forces in the lab. Today's work on air resistance demonstrated that terminal velocity for heavier objects is greater than for lighter objects and that increased air resistance promotes greater air resistance. We'll talk about the lab tomorrow before tidying up final ideas for Newton's 3^rd Law of Motion and beginning to review for the exam on Friday.

Physics E discussed their N-2 and N-3 lab and completed their discussion of Newton's 3^rd Law of Motion. We'll go over the classwork/homework items at the start of class tomorrow, then begin reviewing for Friday's exam.

Physical Science went over their Motion exams and then embarked on a discussion of Newton's 1^st Law of Motion. We will continue with this discussion and add in Newton's ^nd Law in preparation for Thursday's laboratory investigation for N-2.

Homework

Honors Physics: Read lab material
Physics B: Complete Air Resistance lab write up
Physics F: Complete #19, 24, 25, 28, 29, 32, 36 and 37 on pages 84-85 of ancillary packet
Physical Science: None

RIP Edgar Allan Poe

Poe died today, October 7, in the year 1849. Viewed by some as the Great American Hack, he remains one of my all-time favorite authors. You can read most of his works for free from Project Gutenberg. Of course, The Raven is probably his best known poem and, yes, I love it dearly. Here's a video of Vincent Price reading The Raven and I've posted the full text after the clip...



The Raven, by Edgar Allan Poe

Once upon a midnight dreary, while I pondered, weak and weary,
Over many a quaint and curious volume of forgotten lore—
While I nodded, nearly napping, suddenly there came a tapping,
As of some one gently rapping, rapping at my chamber door.
"'Tis some visitor," I muttered, "tapping at my chamber door—
Only this and nothing more."

Ah, distinctly I remember it was in the bleak December,
And each separate dying ember wrought its ghost upon the floor.
Eagerly I wished the morrow;—vainly I had sought to borrow
From my books surcease of sorrow—sorrow for the lost Lenore—
For the rare and radiant maiden whom the angels name Lenore—
Nameless here for evermore.

And the silken sad uncertain rustling of each purple curtain
Thrilled me—filled me with fantastic terrors never felt before;
So that now, to still the beating of my heart, I stood repeating
"'Tis some visiter entreating entrance at my chamber door—
Some late visiter entreating entrance at my chamber door;
This it is and nothing more."

Presently my soul grew stronger; hesitating then no longer,
"Sir," said I, "or Madam, truly your forgiveness I implore;
But the fact is I was napping, and so gently you came rapping,
And so faintly you came tapping, tapping at my chamber door,
That I scarce was sure I heard you"—here I opened wide the door—
Darkness there and nothing more.

Deep into that darkness peering, long I stood there wondering, fearing,
Doubting, dreaming dreams no mortals ever dared to dream before;
But the silence was unbroken, and the stillness gave no token,
And the only word there spoken was the whispered word, "Lenore?"
This I whispered, and an echo murmured back the word, "Lenore!"—
Merely this and nothing more.

Back into the chamber turning, all my soul within me burning,
Soon again I heard a tapping something louder than before.
"Surely," said I, "surely that is something at my window lattice;
Let me see, then, what thereat is and this mystery explore—
Let my heart be still a moment and this mystery explore;—
'Tis the wind and nothing more.

Open here I flung the shutter, when, with many a flirt and flutter,
In there stepped a stately Raven of the saintly days of yore.
Not the least obeisance made he; not a minute stopped or stayed he,
But, with mien of lord or lady, perched above my chamber door—
Perched upon a bust of Pallas just above my chamber door—
Perched, and sat, and nothing more.

Then the ebony bird beguiling my sad fancy into smiling,
By the grave and stern decorum of the countenance it wore,
"Though thy crest be shorn and shaven, thou," I said, "art sure no craven,
Ghastly grim and ancient Raven wandering from the Nightly shore—
Tell me what thy lordly name is on the Night's Plutonian shore!"
Quoth the Raven, "Nevermore."

Much I marvelled this ungainly fowl to hear discourse so plainly,
Though its answer little meaning—little relevancy bore;
For we cannot help agreeing that no living human being
Ever yet was blessed with seeing bird above his chamber door—
Bird or beast upon the sculptured bust above his chamber door,
With such name as "Nevermore."

But the Raven, sitting lonely on that placid bust, spoke only
That one word, as if its soul in that one word he did outpour
Nothing farther then he uttered; not a feather then he fluttered—
Till I scarcely more than muttered: "Other friends have flown before—
On the morrow he will leave me, as my Hopes have flown before."
Then the bird said "Nevermore."

Startled at the stillness broken by reply so aptly spoken,
"Doubtless," said I, "what it utters is its only stock and store,
Caught from some unhappy master whom unmerciful Disaster
Followed fast and followed faster till his songs one burden bore—
Till the dirges of his Hope that melancholy burden bore
Of 'Never—nevermore.'"

But the Raven still beguiling all my sad soul into smiling,
Straight I wheeled a cushioned seat in front of bird and bust and door;
Then, upon the velvet sinking, I betook myself to linking
Fancy unto fancy, thinking what this ominous bird of yore—
What this grim, ungainly, ghastly, gaunt, and ominous bird of yore
Meant in croaking "Nevermore."

This I sat engaged in guessing, but no syllable expressing
To the fowl whose fiery eyes now burned into my bosom's core;
This and more I sat divining, with my head at ease reclining
On the cushion's velvet lining that the lamp-light gloated o'er,
But whose velvet violet lining with the lamp-light gloating o'er
She shall press, ah, nevermore!

Then, methought, the air grew denser, perfumed from an unseen censer
Swung by Seraphim whose foot-falls tinkled on the tufted floor.
"Wretch," I cried, "thy God hath lent thee—by these angels he hath sent thee
Respite—respite and nepenthe from thy memories of Lenore!
Quaff, oh quaff this kind nepenthe and forget this lost Lenore!"
Quoth the Raven, "Nevermore."

"Prophet!" said I, "thing of evil!—prophet still, if bird or devil!—
Whether Tempter sent, or whether tempest tossed thee here ashore,
Desolate, yet all undaunted, on this desert land enchanted—
On this home by Horror haunted—tell me truly, I implore—
Is there—is there balm in Gilead?—tell me—tell me, I implore!"
Quoth the Raven, "Nevermore."

"Prophet!" said I, "thing of evil!—prophet still, if bird or devil!
By that Heaven that bends above us—by that God we both adore—
Tell this soul with sorrow laden if, within the distant Aidenn,
It shall clasp a sainted maiden whom the angels name Lenore—
Clasp a rare and radiant maiden whom the angels name Lenore."
Quoth the Raven, "Nevermore."

"Be that our sign of parting, bird or fiend!" I shrieked, upstarting—
"Get thee back into the tempest and the Night's Plutonian shore!
Leave no black plume as a token of that lie thy soul has spoken!
Leave my loneliness unbroken!—quit the bust above my door!
Take thy beak from out my heart, and take thy form from off my door!"
Quoth the Raven, "Nevermore."

And the Raven, never flitting, still is sitting, still is sitting
On the pallid bust of Pallas just above my chamber door;
And his eyes have all the seeming of a demon's that is dreaming
And the lamp-light o'er him streaming throws his shadows on the floor;
And my soul from out that shadow that lies floating on the floor
Shall be lifted—nevermore!

A Flurry of Lab Work

Honors Physics conducted a lab investigation on Newton's 3^rd Law of Motion. Students used two force sensors to examine action and reaction forces and saw that, yes, they are equal in magnitude and opposite in direction. Further, yes, they are generated simultaneously - there is no time lag between them. We'll discuss the lab and N-3 in more depth on Tuesday.

Physics B and F conducted their lab investigations on Newton's 2^nd Law of Motion. A force sensor, accelerometer and low-friction cart/track were used to document that there exists a directly proportional relationship between applied force and acceleration and that that the relationship can be used to determine the mass of the object. Have your labs written up by Tuesday. Physics B will do another lab on Tuesday, that will concentrate on air resistance. F Block will finish up the material for this chapter and begin preparation for the chapter exam that will be showing up at the end of next week (for both sections).

Physical Science endured their graded learning experience for Motion. On Tuesday, we begin to examine forces in detail and use Newton's Laws of Motion to relate forces to the concepts we studied in Chapter 10 on motion.

Homework

Honors Physics: Complete lab write up
Physics B and F: Complete lab write up
Physical Science: Complete the Pre-Reading Questions on page 345

And the Nobel Prize in Physics Goes To...

Andre Geim and Konstantin Novoselov for their discovery of graphene, which is a very, very cool substance...


Read more about graphene and it's discovery

Testing Newton

Physics B and F began a series of lab investigations to verify Newton's 2^nd and 3^rd Laws of Motion. N-3 was the subject of today's work and it was pretty clear pretty quick that the forces produced with two force sensors pulled on each other were equal and opposite. The graphs of force vs. time for each sensor was a lovely mirror image of its partner. Tomorrow, N-2 will be checked using a force sensor and accelerometer.

Honors Physics reviewed their N-2 problems before starting work on N-3. Since my voice is limping badly, students did the introductory work themselves and I'll take up the load tomorrow.

Physical Science went over their exam preparation homework, before tossing out remaining questions in preparation for the exam. Starting Tuesday, we'll be knee deep in forces!

Homework

Honors Physics: 4.3 Section Review and Chapter Review items #13, 17, 18
Physics B and F: Complete test corrections
Physical Science: Prepare for exam

We're Here?

Ok, today was a mess from the word go. I couldn't find anything and I surely couldn't think straight with the mess surrounding me, but kudos to you guys for being the mature ones and not razzing me for being a big wacky. Expect a good bit of wacky for a while to come as I try to organize things to most efficiently use the space. Let me know if you have any ideas!

Honors Physics took time to look at Newton's Second Law of Motion. Acceleration is directly proportional to net applied force and inversely proportional to the object's inertia (got it right that time!). Though we know this from a common sense perspective, the mathematical application of Newton's 2^nd Law gives us a way to quantitatively predict the response of an object when a net force is applied. As we talked about in class, problems involving N-2 first have you calculate the net force using vector techniques, find the object's resulting acceleration, then apply that acceleration to a kinematics formula to solve to some other property of the object's motion. We'll check over the homework problems tomorrow and march on with the idea of forces.

Physics B discussed Newton's 3^rd Law of Motion. The idea that inanimate objects can apply a force is unusual to many of us, but we discussed many examples today that demonstrate that is actually the case. We also hit some of the major misconceptions surrounding N-3 and how to work with N-3 when analyzing the motion of objects interacting with each other. Tomorrow (fingers crossed!) we will begin a set of lab investigations looking at Newton's 2^nd and 3^rd Laws of Motion.

Physics F took time to discuss their lab investigation on air resistance, before jumping into a discussion on air resistance and how it affects the motion of falling objects. In the absence of air resistance, all objects fall to Earth with the same acceleration - not something that comes naturally to the mind, but we looked at the math to verify that this is true. With air resistance, heavier objects hit the ground first, and we explored why this occurs using the idea of balanced and unbalanced forces. As a brief aside, pressure was differentiated from force, clearing up the misconception that these terms are synonymous. We'll return to pressure in detail when we study forces in fluids. Tomorrow - Newton's 3^rd Law of Motion.

Note for both Physics sections - looking over the Projectile Motion exam today with a student, I decided that one question was deserving of being voted off the island. So, the question #25 has been disqualified and everyone's score has been raised by 3 points. You do not need to make corrections for that particular problem.

Physical Science reviewed the concept of friction and its types before launching into a general review of the chapter in preparation for Thursday's exam. We went page by page through the book highlighting relevant vocabulary, concepts, formulas and graph analysis skills that are ripe for assessment. We'll go over the review homework in class tomorrow and attack any questions that people bring with them.

Homework

Honors Physics: Chapter 4 Review items #19-22, 25
Physics B and F: None
Physical Science: Chapter 10 Review items #1-11, 32

The Final Monday

The great room move is supposedly taking place as I type. So, we should be in the Tech Lab tomorrow...

Honors Physics completed their discussion of free-body diagrams and checked over the diagrams they had made for a prior homework assignment. Attention then turned to the first of Newton’s Laws of Motion, sometimes called the law of inertia. Objects move with constant velocity unless acted on by an net external force. His 2nd Law of Motion allows one to predict exactly the value of the acceleration that net force produces. To creep to up Newton-2, we ended the period by discussing the concept of inertia and relating it to an object’s mass. Tomorrow, we’ll bundle it all up with the 2nd Law of Motion.

Physics B spent time reviewing the concept of friction, before looking in more detail at air resistance. We’ll hit this area again a little later when we discuss gravity, but it is a nice example to use to investigate the fact that friction can act as a balanced or unbalanced force and what are the consequences of each situation. Another topic we’ll take up later is pressure, but it was mentioned in this section because a lot of folks think that “pressure” and “force” are synonyms. Each, actually, has its own, unique meaning in physics and the force/area relationship will be one we investigate in detail when we discuss fluids.

Physics F conducted a lab on air resistance. Unsurprisingly, from our everyday experience, heavier objects fell faster than light objects and the stack of five coffee filters fell with higher terminal velocity than a single filter. The value of the terminal velocity was easy to compute from the position-time graphs using linear regression and the data showed that the coffee filters mass was direction proportional to the terminal velocity squared (T_v²). Then, students got to have a little fun with air resistance by building a parachute and investigating how its terminal velocity was affected by increasing mass. Tomorrow, we’ll go over the lab and have a little more discussion on air resistance and friction.

Physical Science went over their friction labs and took time to reflect on what makes a good results summary and conclusion section to the lab synopsis. Remember – the results summary says in a sentence or two what pattern or relationship was documented by the experiment and the conclusion explains why the relationship exists. We then reviewed the concept of balanced and unbalanced forces and discussed the origin of frictional resistance. Static and kinetic friction were contrasted and examples were studied of each type. Tomorrow, we’ll continue working with motion and forces, with some focused practice in preparation for Thursday’s exam.

Homework

Honors Physics: None
Physics B: In Packet: p. 71, 72 #3, 5, 8, 9-13, 16, 17
Physics F: Complete Air Resistance lab write up
Physical Science: Nones

The Force is the Force, of Course, of Course

Honors Physics conducted a lab investigation that had students graphically analyze vector combination. Using spring scales and a known mass, precisely-drawn vector diagrams were used to demonstrate that adding the force vectors measured by the spring scales summed to the vector describing the object's weight. Further combinations verified that vectors can be added in any order and allowed students some practice with vector subtraction. We'll discuss the lab tomorrow before beginning our lecture unit on forces. Note: you don't need to do a lab synopsis for today's investigation.

Physics B and F began a discussion of forces, inertia and acceleration. We delved a little into the history of the concept of inertia and how inertia determines an object's acceleration (based on applied net force) and will expand on this tomorrow in a more quantitative fashion.

Physical Science reviewed their vector and acceleration worksheet before taking their quiz. After the quiz, the concept of forces was introduced. We'll spend an entire chapter on forces soon, but this preface serves to identify some common forces, highlight the vocabulary terms net force, balanced force and unbalanced force and give a hint as to the nature of forces' ability to affect motion.

Homework

Honors Physics: Complete Adding Force Vectors lab questions
Physics B and F: Complete Chapter 4 Chapter Review items #1-8, 12
Physical Science: Complete Chapter 10 Chapter Review items #17-20

Let the Sunshine In

At least for today. Tomorrow, we're back into the wet and rainy...

Honors Physics took their Chapter 3 exam and the results were interesting. For all of the turmoil about the mathematics part, where some folks didn't fare well was in the basic information. Make sure that when you prepare for a physics test that you budget time for both the content and the mathematics. The test will always have both and one cannot be neglected for the other. Tomorrow, we take up a new topic - Forces!

Physics B and F endured their Projectile Motion exams, then looked ahead towards our work with forces. We've just been concentrating on describing motion; now we tackle the bit of nature that starts, stops and changes the direction of motion. We'll look at various specific forces during the year like gravity, friction, electric force, etc., and you'll they all boil down to pushes or pulls that affect matter's motion.

Physical Science spent time looking at graphs that presented accelerated motion. For a position-time graph, you'd see a curve. For an velocity-time graph, we'd expect a linear relationship for constant acceleration. A velocity-time graph gives me the ability, as well, to calculate the value for that acceleration (the slope of the line) and the displacement (the area under the curve). We'll go over this sheet tomorrow before you take your velocity and acceleration quiz.

Homework:

Honors Physics, Physics B and Physics F: Read 4.1 and complete #1-3, 5, 6 of the 4.1 Section Review
Physical Science: Complete the Velocity and Acceleration worksheet

Prepping for Tests

Honors Physics, Physics B and Physics F all worked on review material for their exams. Then, we all move into forces and begin to explore how all of these changes in motion we've been observing quantifying are being promoted.

Physical Science reviewed their acceleration problems before taking an introductory look at graphs of accelerated motion. You should be able to interpret position-time and velocity-time graphs for accelerated motion and calculate the acceleration and displacement from velocity-time graphs. We'll be practicing this tomorrow and do a spot check on the mathematics of velocity and acceleration with a quiz on Thursday.

Homework

Honors Physics, Physics B, Physics F: Prepare exam
Physical Science: None

Monday + Rain = Yuck

Everyone was either cranky, sleepy or both. And the whole week looks to be the same...

Honors Physics reviewed their projectile problems and were given time to brainstorm solutions for those they had missed. Remember that if you get stuck while working, check the worked-out solutions provided on the course website. Sometimes just a little help with one step open the rest of the problem right up.

Physics B began their review for Wednesday's exam. We walked through the chapter highlighting the relevant test material and specifying which math skills will be required to handle the test problems. Students were give a review packet to work through and class time will be allotted tomorrow to continue that work or to get individual help with chapter topics.

Physics F concluded the chapter with a discussion of satellite motion. Satellites are just fancy projectiles - they move 2-dimensionally, with acceleration provided only by gravity. The descriptors of projectiles that we've been discussing all chapter long apply to satellites in the same way they'd apply to a kicked football. We also took time to examine the chapter to highlight the material relevant for the exam and the math skills that will need to be demonstrated. A review packet was distributed and students will have class time tomorrow to work on it and get individual help with remaining issues with the material.

Physical Science built on Friday's discussion of acceleration and practice acceleration problems by reviewing problem-solving techniques and examining how the MCAS formula sheet presents the acceleration formula. Students were then given a packet of problems that require they demonstrate their ability to use the acceleration formula and snuck in some of those pesky metric conversions, too. The solutions to the problems are presented below and we'll review these problems in class tomorrow before taking a look at adding acceleration to our motion graphs.

Acceleration Worksheet Solutions

1. 44 m/s
2. 10.4 m/s
3. 49.8 km/hr
4. 39.5 s
5. 3.89 s
6. 51 s
7. 3.71 m/s²
8. -21 m/s²
9. 0.1 m/s²
10. 44 m/s
11. 120 s or 2 min
12. 4.5 s
13. 12.5 m/s
14. 47.6 s
15. 4.3 s
16. -490 m/s²
17. 3 m/s
18. -1.0 x 10^-6cm/y²

General problem solving hints:

• Read the problem completely through before starting work.
• Choose the most likely formula to solve for desired variable - it should ask for information that you're given in the problem.
• Write the formula down on paper.
• Read through the problem again and label the information that's presented (initial velocity, time, displacement, etc.)
• Using the formula as a template, match the labeled information to its location in the formula and write the filled- in version of the formula on your paper.
• Perform the necessary algebra to isolate the variable for which you're trying to solve.
• Check that the unit you get matches the unit for your desired answer.
• Check that the answers matches the general pattern you'd predict for situation given in the problem (solving for the velocity of a walking elephant should not yield 500 m/s, for instance).

Good luck!

Homework

Honors Physics: None
Physics B and F: Complete exam review material by Wednesday
Physical Science: Complete acceleration worksheet

Phriday!

Finally!

Honors Physics discussed the concepts behind projectiles launched at an angle before applying these ideas, along with vector operations and kinematics to solving problems with vertically-launched projectiles. When working these problems, make sure to accurately identify all information and account for any implicit information the problem does not mention. For certain problems (like #2, the golf ball problem), there might not seem to be enough information given or assumed. Think back to the little trick of redefining one variable in terms of another to derive a single-variable equation. We'll go over these on Monday and then spend a little time talking about relative motion.

Physics B discussed the idea of satellite motion, a special case of projectile motion. Physics F looked conceptually at projectiles launched at an angle, where some of the assumptions we made for horizontally-launched projectiles are not longer applicable. We'll hit satellite motion on Monday. The exam, currently scheduled for Wednesday, will definitely feature vector operations. An optional worksheet was provided today for vector combination and vector resolution and the solutions are presented below:

1. a. 76.5 N at 78.7° SW b. 85 m/s left c. 18 m at 33.7° NE
2. a. 140 m W; 660 m N b. 311 m E; 69 m S c. 26.8 km E; 22.5 km N
3. 5.6 m at 63.4° NE
4. 14.5 m/s upwards
5. 5.6 m/s across the ground
6. 243.5 m/s at 70.8° SW

Physical Science reviewed their motion and velocity homework before discussing the nature of scalars and vectors. Scalars have magnitude only, while vectors add direction to the magnitude measurement. Displacement and velocity are vectors; distance and speed are scalars. The addition of the direction component allows for vector combination - studying the effect of one object on the behavior of another. We then began to examine a new vector quantity - acceleration. We'll dig into acceleration in more detail on Monday.

Homework

Honors Physics: Practice 3E
Physics B: p. 41, 42 in packet #15-18, 26, 41
Physics F: p. 41, 42 in packet #8 - 18, 26, 41
Physical Science: None

Hitting the Target

Physics F completed their projectile motion lab activity, which had students measure the launch velocity of a horizontal projectile and predict its landing point on the floor. They had to hit the target in one go and students did a very good job with their calculations to make that happen. Tomorrow, we'll review the lab and then take a loot at projectiles launched at an angle.

Physics B completed their discussion of horizontally-launched projectiles before moving to projectiles launched at an angle. That situations is a bit more complicated than for horizontal projectiles, but it can still be thought of simply as an object in free fall that happens to have a horizontal component to its velocity. The motion is still parabolic and, provided the launch and landing points are at the same height, symmetrical. We'll review this a little tomorrow before moving on to satellite motion.

Honors Physics reviewed their vector combination work and took time to start applying these ideas to horizontal projectiles. When you are working with horizontally-launched projectiles, there are bits of information you can count on:

• Horizontal velocity remains constant (if air resistance is negligible)
• The initial velocity in the y-direction is 0 m/s
• The acceleration in the y-direction is -9.81 m/s²

With those bits, calculating things like time in the air and range become simple, as you saw for your projectile motion lab. We'll review your horizontal projectile homework problems tomorrow before moving on to projectiles launched at an angle.

Physical Science reviewed their Graphing Your Motion investigations before and spent time reviewing the basic vocabulary and mathematics of distance/displacement and speed/velocity. Tomorrow, we pick up with the vector nature of velocity (and the scalar nature of speed), before dipping our toes in acceleration.

Homework

Honors Physics: Practice 3D
Physics B: p. 40 of ancillary reading packet #8 - 14
Physics F: Complete Projectile Motion lab write up
Physical Science : Chapter 10 Review items #12, 15, 16, 24, 25, 26, 30

Apollo 13

I have all episodes of Mythbusters in my Amazon Video on Demand library and was watching the one where they investigated the myths about the US faking the moon landings. Got me reminiscent about the movie Apollo 13, which, if you don't know, is a true story. Maybe its my age or my disposition, but that stands as one of the few movies that makes me put down whatever I'm doing and watch it when I come across it on TV. I have some nebulous memories of the actual moon landings and that film encapsulates what I remember about the atmosphere in the country about the NASA programs and the moon shots, specifically. If you haven't watched Apollo 13, set aside the time to catch it one day. I don't think you'll be sorry you did...

Constant Velocity is Hard!

Physical Science worked on a lab that had students examine graphs of their own motion and, in a difficult twist, copy the motion described by graphs give to them. Using a motion detector, students examined distance-time and velocity-time graphs of slow and fast motion and then were given distance-time and velocity-time graphs that they had to act out in real time. The computer traced their actual motion against the "recipe" and students had to refine their technique to match the graphs as best they could. So, everyone got a lot of practice interpreting motion graphs and getting a feel for what these graphs are actually describing. Tomorrow, more with motion and perhaps a little peek at acceleration...

Honors Physics took one last look at their Projectile Motion lab before jumping into vector operations. Vector combination and resolution were discussed, as was the combination of non-perpendicular vectors. Tonight's homework will allow opportunities to practice all these techniques before use them to help analyze examples of projectile motion.

Physics B and F went over their vector worksheets before turning attention to horizontally-launched projectiles. Knowing something is a horizontally-launched projectile puts some information in your back pocket - the horizontal velocity remains constant, the vertical accelerations is free-fall acceleration and the initial velocity in the horizontal direction is 0 m/s. That helps tremendously with problem solving. We took time also to explain what is and what is not a projectile and explore why projectile motion takes the path of a parabola. Tomorrow, Physics B will move into the area of projectiles launched at an angle and Physics F will conduct their lab investigation for projectile motion.

Homework

Honors Physics: Practice 3A #1, 3; Practice 3B #2, 5, 7; Practice 3C #2, 3, 4
Physical Science: Complete Graphing Your Motion lab write up
Physics B: p. 41, 42 in Packet #29, 30, 39
Physics F: Read Projectile Motion lab protocol sheet

More Projectiles

Honors Physics conducted their projectile motion lab, and added a twist at the end. Students were first tasked to predict the landing point for a horizontally-launched projectile, when they only measured table height and launch velocity (catching ball in hand - no cheating by letting it hit the floor). All groups nailed their targets. Then, students were given a landing point and had to calculate the requisite launch velocity and calibrate their ramp system to deliver. Again, all groups hit their target, through a few were helped by having a fairly wide cup to hit. So, lots of prizes were disbursed and lots of learning was provided to all concerned. With the independence of the velocity vectors, a situation involving 2-dimensional motion is actually pretty easy to analyze. Tomorrow, we'll do more work with vector operations and will apply these techniques to a slightly more complex form of projectile motion - projectiles launched at an angle.

Physics B went over their projectile motion labs and then turned attention to practicing combining and resolving vectors. We'll go over worksheet tomorrow in class, so if you have problems with some of the items, make sure to ask about them to make your corrections.

Physics F discussed yesterday's vector worksheet and students were allowed to hold onto them if they wanted to work through the items again. A second sheet was distributed for additional practice, both in drawing vector diagrams and in mathematically analyzing vector-based situations.

Physical Science addressed any last questions for their Chapter 1 exams before moving into motion. The vocabulary for this chapter can be confusing, since may terms are considered synonymous in daily use, but actually have significantly different meanings. Distance/displacement, speed/velocity are examples that come to mind. Be very clear to use the proper term when describing motion and that you are using the correct definition when solving motion problems. Students also discussed the importance of a frame of reference and began to look at position-time graphs of linear motion. Tomorrow, a lab is on the docket that will let students create and analyze graphs of motion.

Homework

Honors Physics: Complete lab write up
Physics B: Complete Vectors worksheet
Physics F: Complete new vector worksheet
Physical Science: Math Practice p. 323 and the 10.1 Section Review on p. 324

Monday, Monday

...can't trust that day...

Honors Physics reviewed their Chapter 1,2 exams before starting in on our unit for 2-dimensional motion. Analyses of 2-dimensional motion require the use of vectors, so we began looking at vectors today after the review. Vectors, with a magnitude and direction, allow for the study of behaviors of objects in response to interactions with other objects in their system. We discussed the property of vectors, the construction of vector diagrams and the graphical method of finding resultants. Tomorrow, we'll dig in deeper into vector analysis with a look at the mathematical methods of combining and resolving vectors.

Physics B and Physics F got back their Chapter 1,2 exams and have until Thursday to make any corrections to bolster their current score (optional). In class, Physics B conducted a lab investigation that centered on projectile motion. A horizontally-launched projectile was studied and predictions were made about its landing point. The initial horizontal velocity of the projectile, a ball bearing, was determined using photogates and students had to then calculate its predicted end point on the classroom floor. Very good results were had with two groups hitting their target dead center! We will discuss the lab tomorrow and get some practice working with vectors before turning further attention to projectile motion. Physics F worked with vector combination and resolution. We'll go over the worksheet tomorrow and address any final questions with basic vector operations before applying these ideas to projectile motion.

Physical Science was a split class. Since half of the class missed the exam on Friday, those students took the Chapter 1 exam. The remaining students received their exams back and were allowed, for this first test of the year, to make corrections to bolster their score. This will be the only such opportunity, so make the most of it! Everyone's test corrections are due tomorrow, before we move into our study of motion.

Homework

Honors Physics: None, besides read Projectile Motion Lab handout
Physics B: Complete Projectile Motion lab
Physics F: Complete Vectors worksheet
Physical Science: Complete test corrections

And the Testing Continues

Honors Physics and Physical Science took their first unit exams today. On Monday, Honors Physics tackles vectors and Physical Science jumps into motion.

Physics B and F were introduced to the concept of vectors. Values with magnitude and direction are vectors (ex. velocity, acceleration, force, momentum) and those lacking direction are scalars. Vectors offer the advantage of letting you examine a system where matter interacts with matter. We looked at the graphical methods of vector combination and resolution, but spent more time detailing the mathematical way to analyze vector problems. Refresh your memory on the Pythagorean Theorem and the basic trig functions (sine, cosine, tangent) in preparation of further work with vectors. Once you have the techniques down, they can be applied to anything that is vector in nature. On Monday, B Block should be conducting a lab on projectile motion and F Block will be getting some practice working with vectors.

Homework

Honors Physics: Read sections 3.1 and 3.1 and complete Chapter Review #1, 2, 4, 11, 12

Physics B and F: None
Physical Science : None

And the Tests Begin!

Physics B and F took their Chapters 1 and 2 exams today. Remember to complete and turn in your bonus packet tomorrow if you want the credit. Tomorrow, we add a dimension (literally) to our study of motion. In order to understand projectile, or 2-dimensional motion, you must first understand vectors and that will be our first order of business.

Honors Physics reviewed the homework problems, then walked through Chapters 1 and 2, highlighting and reviewing material for tomorrow's exam. Don't forget to have the past two night's homework with you to hand in before the exam and don't forget your calculators!

Physical Science reviewed their study packet for tomorrow's exam and then we moved through the chapter detailing and reviewing material that will appear on tomorrow's test. You were allowed to keep your study packet, but remember to hand it in tomorrow before the test for credit.

Homework

Honors Physics: Prepare for exam
Physics B and F: Read p. 28-32 in your packet and complete #1-6, 30 on pages 40 and 41 of the reading
Physical Science: Prepare for exam

Reviews

Honors Physics, upon going over their free-fall homework problems, decided that further review was required. The exam has been moved to Friday and we will discuss the problems assigned tonight and conduct a general review of the material tomorrow in class.

Physics B and F reviewed their respective lab exercises, then took time to walk through the material to highlight topics for tomorrow's exam. The review packet given is bonus work, that will be due on Friday.

Physical Science went over their scientific notation and significant figures homework, then began working on a review packet for Friday's exam. We will go over this packet as part of a general review for Friday's test tomorrow in class.

Homework:

Honors Physics: Chapter Review #20, 22, 29, 38, 42, 46
Physics B and F: Prepare for exam
Physical Science: Complete exam review packet

A Day o' Labs

Honors Physics and Physics B conducted their investigation of free-fall acceleration and verified that objects fall with constant acceleration, not variable acceleration or constant speed. We would witness constant speed in free fall only when an object reached terminal velocity, the speed at which the force or air resistance balances the object's weight. We'll look at that idea later when we discuss forces in detail.

Physics F conducted a lab investigation that allowed students to create three graphs describing a single motion - a cart moving up and back down a low-friction incline. Each graph provided vital information about the cart's motion, and all reinforced the idea that the acceleration of the cart was constant throughout its travel. Graph interpretation is a vital skill in physics and these past couple of labs have provided lots of opportunity to practice the skill.

Physical Science discussed yesterday's lab investigation before looking over the independent graphing homework. Make sure you are able to create a graph that follows all the guidelines for effective graph design and that you are able to choose the right type of graph for the data set. Of course, the fun really begins with graph interpretation and that is something we will work on all year.

Homework
Honors Physics: Complete lab writeup and free-fall problems assigned Friday
Physics B: Complete lab writeup
Physics F: Complete lab writeup
Physical Science: p. 29 #24-27

The First Full Week

After two shortened weeks, we get the full experience starting today. Unfortunately...

Honors Physics discussed the concept of free fall and tied the information in with the basic motion topics we have covered already. Any of the kinematics equations can be used to work with free-fall problems and you always know the value for the object's acceleration. Remember that the acceleration due to gravity is the same magnitude and direction, regardless if the object is rising or falling. The only difference is in the effect on the object's motion - ascending objects lose speed and descending objects gain speed. We discussed the symmetry of the motion in detail today, and that will be quite helpful when we begin our discussion of projectile motion. Tomorrow, a lab that permits folks to validate the accepted value for acceleration due to gravity.

Physics B spent time discussing the concept of air resistance, one example of a friction force opposing an object's motion. The effect of air resistance on an object depends on the object's mass, speed, size and shape and demonstrations were presented in class to highlight these factors We will discuss air resistance again when we cover the force of friction and add in the idea of terminal velocity. Tomorrow, a short lab that lets students measure acceleration due to gravity in a relatively-low air resistance system.

Physics F conducted a lab investigation into the accepted value for acceleration due to gravity. Using a photogate, the motion of a falling object could be examined and it was found that objects dropped from a height do accelerate and the magnitude of that acceleration fell within a measure of standard error to the accepted value of 9.81 m/s². Students examined position, velocity and acceleration versus time graphically and each graph reinforced the conclusions presented by the others. We'll conduct another investigation tomorrow, that will also allow graphical analysis of motion - the motion of a cart up a ramp.

Physical Science conducted a lab investigation that permitted students to investigate more functions of the Vernier system when they tested the effect of length on the period of a pendulum. Using a motion detector, students were able to use the computer-generated sinusoidal graph to measure period for a variety of pendulum lengths and to fit equations to the data. We'll discuss the lab in class tomorrow, along with the graphing homework, before moving on to scientific notation.

Homework

Honors Physics: Practice 2F #5; 2.3 Section Review
Physics B: p. 25-26 of packet # 22, 23, 24, 47, 49
Physics F: Complete lab write up
Physical Science: Complete graphing assignment from Friday