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Bouncing Balls
Bouncing Balls

Some balls bounce better than others.

A particular ball can be characterized by its

    coefficient of restitution:
The ratio of its rebound speed Vf to its collision speed Vi
    when its bounces off a hard, stationary surface that can't move.
    coefficient of restitution r = Vf / Vi
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 bluearrow ( represent its velocity)
      and drag it left/right.
3. You can change the initial height  (drag it up and down with mouse left click)

4. 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 timing 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¡GFu-Kwun Hwang, Dept. of physics, National Taiwan Normal University
Last modified : 


Subject: bouncing ball
Date:  Fri, 21 Apr 2000 05:01:29 -0400
From: David and Carol <blood@boone.net>
To: hwang@phy03.phy.ntnu.edu.tw

http://www.phy.ntnu.edu.tw/java/bouncingBall/bouncingBall.html 

the above site has been helpful in a differential equations project I am
currently undertaking. One thing that would make your applet invaluable to
me is if heights were marked on the picture of the bouncing ball. I am
measuring the height of a ball and am trying to find it's coefficient of
restitution. Is there anyway of setting initial heights on your applet and
finding the maximums of each consecutive bounce?

thank you,
David
The code was modified according to David's suggestion Apr. 21, 2000
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