This applet demonstrates projectile motion. Each point
traces out the path of a ball falling in a vacuum. Each
time the ball hits the ground (the x-axis) the ball's
momentum decreases by 20%. This corresponds to a value
of .8 for the * bounce coefficient*, which is reasonable for
most real balls.

In this window, there is air resistance or drag.
The force on the ball is represented by

where g is -9.8 m/s, and b is a positive number that increases with the amount of friction. The

- Try the default settings and watch the particle's path. Notice how the curve is noticeably shortened from a parabola.
- Drop a particle from a height. Watch it as it falls.
If the object stops accelerating and falls at a constant pace,
then it has reached
*terminal velocity*. How high do you have to put the particle to observe this effect?

- Put in values for the original position and velocity.
- Click "New Particle" to make it go.
- To clear the screen, click "Remove All."
- To scroll around, click the buttons on the edge of the graph.
- To set the viewing options, right click on the graph, then click "Settings"

Copyright Robert J. McGrew 1998

Last Modified: 6/15/98

For help, contact: cerkal@ossm.edu