Open a parachute half-way through a skydiver's descent. The simulation toolbar also shows the current simulation time. A scrolling graph records how the vertical position, velocity and acceleration of the ball change with time. The ball's height above the ground is recorded as a positive distance, and an upward force or velocity would also be recorded as positive values. Conversely, a downward force or velocity are negative.
Controls allow gravity, air friction and the mass and size of the ball to be varied.
The air friction control varies the constant of proportionality. Checkboxes provide the options of pausing the simulation every 0.2 seconds, and automatically when the ball hits the ground - useful for making detailed recordings and observations. With the initial settings the ball reaches its terminal velocity before hitting the ground. When the ball hits the ground it loses most of its kinetic energy in a fairly inelastic collision. Should you want to allow the ball an uninterrupted fall you can delete the ground by pausing the simulation, selecting the ground plane with the mouse, and pressing the Delete key.