What Is Terminal Velocity?

When an object is moved through a fluid in a downward direction, it experiences an opposite force. This force is called drag force. As the object accelerates downward, drag force also increases in upward direction. When the drag force becomes equal to the weight of the body, the speed of the body becomes constant. This speed is called terminal velocity. At terminal velocity weight of the body and drag force cancel the effect of each other so, body moves with a constant velocity. Body is in state of equilibrium at terminal velocity. Consider a body moving through a fluid, the net force acting on it is;

net force= weight - drag force

ma= mg- 1/2 pv²AC_d

When drag force is equal to weight, then net force is equal to zero;

mg= 1/2 pv²AC_d

v²=2 mg /pAC_d

v= [2 mg /pAC_d]^1/2

v= terminal velocity

m= mass of object

g=gravitational acelerration

C_d= drag coefficient

A= area of falling object

p= density of the fluid