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