1. PHY221 Ch12: Elastic Collisions

2. 1. Main Points Momentum conservation and KE conservation equations

3. PHY221 Ch12: Elastic Collisions 1. Main Points Equations in CM frame

4. PHY205 Ch12: Elastic Collisions 1. Main Points Equations in CM frame So we have shown that, IN THE CM FRAME, the following describes the outcome of a elastic collision (those statements are NOT true if we don’t put ourselves in the CM frame!!): the initial and final SPEEDs of the objects m1 and m2 are the same: v 1i =v 1f and v 2i =v 2f Since the total momentum is conserved, the final momentum remains ZERO (since the total initial momentum was zero) and thus the final momentum vectors of the 2 objects must be opposite to each other which means that they travel in opposite directions The angle by which the trajectories of the 2 objects are deflected during the collision is not determined by the conservation of energy and momentum. That angle will be the result of the specific type of collision (for instance if 2 billiard balls collide the outgoing velocity directions will depend on the collision geometry)

5. PHY205 Ch12: Elastic Collisions 2. Discuss 1 d and applications: ball bounce and grav sling shot effect

6. PHY221 Ch12: Elastic Collisions Exercises

7. PHY221 Ch12: Elastic Collisions 2. Discuss 2 d General comments

8. PHY221 Ch12: Elastic Collisions 2. Discuss 1d example

9. PHY221 Ch12: Elastic Collisions 2. Discuss

10. PHY221 Ch12: Elastic Collisions Exercises