1. Impulse Elastic Collisions 1 Conservation Collisions

2. Impulse Elastic Collisions 2 Conservation of Linear Momentum The change in momentum of a system is equal to the impulse put on the system.

3. Impulse Elastic Collisions 3 Conservation of Linear Momentum For example: Jeff Bagwell hits a baseball… Initially

4. Impulse Elastic Collisions 4 Conservation of Linear Momentum For example: Jeff Bagwell hits a baseball… During hit

5. Impulse Elastic Collisions 5 Conservation of Linear Momentum For example: Jeff Bagwell hits a baseball… Finally

6. Impulse Elastic Collisions 6 Two types of collisions Elastic: The objects do not stick together or change shape. Momentum and kinetic energy are conserved. Inelastic: The objects do stick together and/or change shape. Only momentum is conserved!

7. Impulse Elastic Collisions 7 Example of an elastic collision The cue ball hits two billiard balls initially at rest on a billiard table. Assume that the cue ball stops after hitting the other balls. What is the final velocity of the red and blue ball? x y θ

8. Impulse Elastic Collisions 8 x y θ

9. Impulse Elastic Collisions 9 x y θ

10. Impulse Elastic Collisions 10 x y θ We have three equations and four unknowns. We cannot solve this problem without more information. You will usually be given the speed or angle of one of the balls.