The document provides an overview and examples of momentum concepts including elastic collisions, inelastic collisions, explosions, and momentum in two dimensions. It defines elastic collisions as "bouncy" collisions where objects move apart with different velocities, and inelastic collisions as "sticky" collisions where objects travel together with the same velocity after impact. Explosions involve objects breaking apart and traveling in different directions at different speeds. Examples are provided for calculating the velocity after an inelastic collision, the recoil speed from an explosion, and the velocities of balls after a two-dimensional collision. Key momentum equations are also presented.

1. Physics Simplified: A review of Unit 5, part II Chapter 9 Section 9.4: Inelastic Collisions Section 9.5: Explosions Section 9.6: Momentum in Two Dimensions Ben Caffrey

2. Tips: To me, one of the hardest parts of momentum is simply conceptualizing and realizing the various types of situations. Just to make sure, here is a breakdown: Elastic Collision: A ‘bouncy’ collision, in which two objects move apart at different velocities. Inelastic Collision: A ‘sticky’ collision, in which two objects travel as a unit, with the same velocity, after the collision Explosion: An instance in which objects that are together break apart, with various parts traveling in different directions with different speeds Remember: Momentum is always conserved. It’s a fundamental law of physics.

3. Equations: Most momentum questions we will encounter can be solved using the equation for the conservation of momentum: For momentum in two dimensions, we must remember that momentum is conserved in both dimensions: First, simple equation for momentum:

4. 9.4 Inelastic Collisions: A 1,000 kilogram truck traveling at 5 meters per second collides with a smaller, 600 kilogram stationary car at a stop sign. The two vehicles begin sliding into the intersection together. What is their initial velocity after the impact?

5. 9.5 Explosions: A 10 gram bullet is fired from a 3.0 kilogram rifle with a speed of 500 meters per second. What is the recoil speed of the rifle?

6. 9.6 Two Dimensions: 30* 45* A cue ball is shot at 5 meters per second into the 8-ball. After the collision, the cue ball veers off at a 30 degree angle north of east at a speed of 3 meters per second. If the 8-ball veers off at an angle 45 degrees south of east, what is it’s speed? Note: Pool balls weigh 160 grams.