Here are some of the basic equations for falling/dropping objects. The variables use the metric system, click here for the default values. The variables are for a human male, falling on the planet Earth. The "Other" list values are for the planet Earth, which uses it's equatorial radius.
FORCE: Notice how terminal velocity is reached once the weight in Newtons is equal to air resistance in Newtons. Once the downward force (weight), and the upward force (air resistance) are equal, there is no more acceleration. Without air resistance (the upward force), acceleration would continue since the upward force of air resistance would remain at zero in a vacuum.
ATTENTION! This simulation can give you an a basic sense of how fast something will fall, it is not extremely precise. Don't try to use this in Internet Explorer, it seems to be too slow and innaccurate. Mozilla Firefox and Apple Safari work fine, the standalone .NET version works fine as well. Also, the .NET version is a little more advanced, it has collision detection and elasticity of collision.