Home / Physics / Applied Force

# Applied Force

## What is Applied Force

An applied force is a contact force that is applied to an object by external means. As a result of applied force, the object either moves or deforms. The object generally moves in the direction of the applied force. Suppose it is lifted from the ground using a pulley. In that case, the motion of the object is opposite to the direction of the applied force.

## Examples of Applied Force

Here are some examples of the applied force.

• Pulling a bucket of water from a well
• Rotating a doorknob by human hand
• Lifting an object from the floor
• Checking the weight of the person (This is a practice way to measure the applied force)
• Pushing a box on a floor

## Applied Force Formula: How to Find the Applied Force

The applied force can be determined using Newton’s laws of motion and the force balance equation in different situations.

### Applied Force Equation

Suppose an object of mass m is pushed through a distance such that its acceleration is a. Then, the applied force is given by,

FA = ma

Friction

Now, if the object is moving on a surface where there is a friction force f, then,

ma = FA – f

Or, FA = ma + f

Gravity

If a string suspends the object, then its weight W is the only force acting on it. The applied force is given by,

FA = W = mg

Inclined Plane

When the object is on an inclined plane, then the component of its weight along the incline is the applied force.

FA = mg sin θ

Work Done by Applied Force

When the applied force displaces an object through a distance x, work is done.

W = FA.x What is the Terminal Velocity of a Human?