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When something falls through a fluid (this can be a gas such as air or a liquid) it does not go on getting faster and faster. If it is falling through air the friction with the air slows it down. The maximum velocity that an object can reach in a given fluid is called its TERMINAL VELOCITY.

When it is falling at their terminal velocity the drag on an object is equal to the weight of the sphere (minus any upthrust due to the fluid).

The terminal velocity for a person falling through air near sea level is about 200 mph head down and about 125 mph lying flat out. A certain personís terminal velocity will be different at different altitudes because of the different density of the air.

© Keith Gibbs 2009