What is terminal velocity?

Terminal Velocity

Terminal velocity is the constant speed that a freely falling object eventually reaches when the resistance of the medium through which it is falling prevents further acceleration. In simpler terms, it's the maximum speed an object reaches during freefall.

How it Works:

Initially, when an object starts falling, the only force acting on it is gravity, causing it to accelerate downwards. As the object's speed increases, the drag force (air resistance in the case of air) acting on the object also increases.

Eventually, the drag force becomes equal in magnitude to the gravitational force. At this point, the net force on the object is zero, and therefore, its acceleration becomes zero. The object continues to fall, but at a constant speed: this is the terminal velocity.

Factors Affecting Terminal Velocity:

Several factors influence the terminal velocity of an object:

Mass: A heavier object generally has a higher terminal velocity because a greater gravitational force needs to be balanced by a larger drag force.
Shape and Size: The shape and size of the object greatly affect the drag force. A more streamlined object will experience less drag and, therefore, a higher terminal velocity. A larger surface area exposed to the airflow also increases drag, reducing terminal velocity.
Fluid Density: The density of the fluid (e.g., air) through which the object is falling also affects terminal velocity. An object will have a lower terminal velocity in a denser fluid.
Surface Area: As mentioned above, a larger surface area increases the drag force.

Examples:

A skydiver reaches a terminal velocity of about 55 m/s (200 km/h or 120 mph) in a belly-to-earth position.
A raindrop reaches a terminal velocity of about 8-10 m/s (29-36 km/h or 18-22 mph), depending on its size.

Importance:

Understanding terminal velocity is important in various fields, including:

Aerodynamics: Designing aircraft and other vehicles to minimize drag and achieve desired speeds.
Parachuting: Calculating the size of parachutes needed to slow down descent to a safe speed.
Meteorology: Predicting the speed and impact of hailstones and raindrops.