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