Some balls bounce better than others.

A particular ball can be characterized by its

coefficient of restitution:

The ratio of its rebound speed V_f to its collision speed V_i

when its bounces off a hard, stationary surface that can'n move.

coefficient of restitution r = V_f / V_i

Scientists have found that, for most balls, this speed ratio

remains constant over a wide range of collision speeds.

The amount of kinetic energy transformed at impact is called

the collision energy (become thermal energy).

This java applet shows you the effects due to

different coefficient of restitution.

1. You can enter different value of coefficient of restitution as(Vo/Vi).

Then, press return key to start the animation.

2. You can change the initial velocity Vx of the ball.

Click near the tip of blue arrow(represent its velocity)

and drag it left/right.

3. Press Start button to start/restart animation.

The animation will stop automatically when it bounces off the screen.

4. Press Reset button to reset parameters to its default value.

It also clear the screen.

5. Press the mouse button to pause the animation

If you click the left mouse button,

animation will resume when you release it.

If you click the right mouse button,

you need to click it again to resume.

6. The mouse coordinate (X,Y) will be shown when its inside the window.

You will know the timeing t from (X and velocity Vx)

You should be able to get some graph like this (click me).

Your suggestions are highly appreciated!

E-mail : Please click hwang@phy03.phy.ntnu.edu.tw

Author：Fu-Kwun Hwang, Dept. of physics, National Taiwan Normal University

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