Terminal Velocity in Free Fall

Terminal velocity is the fastest speed anything can reach in free fall. Every object has a different terminal velocity based on the mass, the gravitational force and drag force. Isaac Newton discovered that gravity was a force applied upon objects in Earth. He also calculated that the rate of acceleration at which objects fall is -9.8m/s^2 or 1 g and the force of gravity on an object is equal to 1g x the mass of the object. This means if you were to fall from space and enter earth you would be speeding up by 9.8 meters every second you are in free fall if Earth had no atmosphere. The air you would fall through would add a resistance to your fall, stopping you from accelerating at 9.8m/s^2.

Air resistance, or drag force, is another variable acting upon objects that are in a state of free fall. Drag force acts against the force of gravity and has many variables that tell how must the object falling will be slowed. The way it works is the drag force counteracts gravity by applying an upward force. The surface area of the object, the speed, the density of the air, and the drag coefficient are the variables that determine the drag force. How aerodynamic the falling object is determines the drag coefficient. The faster an object is falling; the more drag force is being applied on it. The state of terminal velocity is achieved once the drag is equal to the acceleration.

As an object falls the velocity of that object increases and the air resistance increases but the acceleration of the object stays the same. An object falling in free fall toward Earth has a constant acceleration of 9.8m/s^2. Once the drag force becomes equal to the acceleration, the object will stay at the same velocity or terminal velocity. Since the drag force depends on the amount of surface area, weight, the objects aerodynamics, and the density of the air, every object has a different terminal velocity. There are many objects that achieve terminal velocity very quickly and others are made to take longer or not even reach it at all if possible. For instance, a rocket has a very aerodynamic tip that helps it cut through the density of the air as the rocket gains speed. The rocket will reach terminal velocity much slower that a parachute or even a human free falling from space.


 By Rivaldo Gilharry


Article Source: Terminal Velocity in Free Fall