upward drag force equals the downward force of gravity. When this occurs, there is no
net force and the object ceases to accelerate and maintains a constant speed. The
equation for calculating terminal velocity is shown in Equation 2. It is derived by setting
the drag force equal to the object’s weight and solving for the speed.
Research has actually determined that cats reach terminal velocity after falling six
stories. In fact, they tend to slow down after six stories. Here’s why this occurs: The cat
achieves terminal velocity and then relaxes a little, which expands its cross sectional
area and increases its drag force. As a result, it slows down. One has to admire the cat
for relaxing in such a precarious situation (or perhaps doubt its intelligence). If you think
this may be an urban legend, consult the Journal of the American Veterinary
Association, volume 191, page 1399.
Terminal velocity
Drag force equals weight