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