- terminal velocity
-
1. Physics.a. the velocity at which a falling body moves through a medium, as air, when the force of resistance of the medium is equal in magnitude and opposite in direction to the force of gravity.b. the maximum velocity of a body falling through a viscous fluid.2. Rocketry, Ballistics.a. the greatest speed that a rocket, missile, etc., attains after burnout or after leaving the barrel of a gun.b. the speed of a missile or projectile on impact with its target.
* * *
▪ physicssteady speed achieved by an object freely falling through a gas or liquid. A typical terminal velocity for a parachutist who delays opening the chute is about 150 miles (240 kilometres) per hour. Raindrops fall at a much lower terminal velocity, and a mist of tiny oil droplets settles at an exceedingly small terminal velocity. An object dropped from rest will increase its speed until it reaches terminal velocity; an object forced to move faster than its terminal velocity will, upon release, slow down to this constant velocity.Terminal velocity is achieved, therefore, when the speed of a moving object is no longer increasing or decreasing; the object's acceleration (or deceleration) is zero. The force of air resistance is approximately proportional to the speed of the falling object, so that air resistance increases for an object that is accelerating, having been dropped from rest until terminal velocity is reached. At terminal velocity, air resistance equals in magnitude the weight of the falling object. Because the two are oppositely directed forces, the total force on the object is zero, and the speed of the object has become constant.* * *
Universalium. 2010.
