Terminal Velocity

Key Stage 4

Terminal velocity is the velocity a falling object reaches when the forces of drag and weight on that object are balanced.

Terminal velocity depends on:

The density of an object - The more dense an object the greater the terminal velocity because larger objects will experience greater air resistance at a given speed.
The shape of an object - The more streamlined an object the greater the terminal velocity because they experience less air resistance at a given speed.

Terminal velocity is the maximum velocity an object will reach when falling due to gravity.

Terminal velocity occurs because air resistance increases with speed until the air resistance is balanced with the weight, at which point the object will stop accelerating.

This penguin has just jumped out of a plane.
	At the start the penguin is not yet moving and the only force acting on the penguin is its weight. Resultant Force = Weight So the resultant force is large which means the acceleration will be large.
	As the penguin starts to accelerate its small velocity results in an air resistance that acts against its weight. Resultant Force = Weight - Air Resistance So the resultant force is less than it was so the acceleration will be less.
	As the penguin accelerates more its hight velocity results in more air resistance that acts against its weight. Resultant Force = Weight - Air Resistance So the resultant force is even smaller than it was so the acceleration will be smaller.
	Once the penguin is moving fast enough the velocity results in an air resistance that is as large as the weight. Resultant Force = Weight - Air Resistance Resultant Force = 0N So there is no resultant force and so the acceleration will be zero. The penguin has reached terminal velocity.