Drag the mass with the mouse to its new starting position.
motion, the mass can be 'caught' by clicking and holding it with the
You can also change the angle of the floor by dragging in the
horizontal direction on the bar under the "dip" in the floor.
This applet shows the mass bouncing from the walls of the box. The
mass moves under the force of gravity, and all collisions are
elastic. The angle at which the mass hits the surface is equal to the
angle at which it leaves the surface.