Unit 4: Systems of Particles
In order to understand much of the world around us, we need to know how particles relate to each other. Large scale objects can be thought of as particles if we find a position for each one called cm (the center of mass.) We will use calculus to determine the cm position for common geometric objects and then show how Newton's Laws can be applied to the parameters describing the cm motion. Additionally, we have to introduce a new idea called momentum that is a conserved quantity whenever the particles inside a system exert internal forces on each other, but changes whenever external forces are applied. Taken in total, these ideas will allow us to describe such diverse topics as car crashes, explosions, billiards, and the importance of "follow-through" in golf, baseball and tennis.
Suggested timeframe: 3 weeks
1. The center of mass of an object moves as if all the mass of the object was located there.
2. Momentum of an object is the product of the mass and velocity of that object.
3. All collisions of objects exhibit conservation of momentum.