**COR
and the Physics of Bounce**

**Obj:**
Determine COR of several energy balls; graphically analyze a
bounce

**Materials**: various bounce balls, high energy balls,
meter stick

**Methods
and Analysis**

** I. Coefficient
of Restitution COR** (v

1. Mass the high energy ball. Place vertically a meter stick on the lab table.

2. From 1 meter, drop the ball, then accurately determine and record the height to which it returned.

3. Repeat four times,

4.

i. Determine the impact velocity and the upward bounce velocity.

ii. Plot a graph of v

iii. calculate the amount of kinetic energy lost (mgΔh) upon each bounce and the percent.

5. Where is the lost kinetic energy going? Is bouncing

6. Suggest a formula for COR using the

7.

8. For a perfectly elastic collision what is the COR.

9. On your graph, sketch a line for a perfectly elastic collision and one that is totally inelastic.

10. Most rubber products have a specific heat of 1600 J/kg