When a force is exerted on an object and the object moves in the direction of the force, work is said to be done. Work is a measure of the energy transferred from the force to the object. The amount of work done is calculated by multiplying the magnitude of the force applied to the object by the distance the object moves in the direction of the force.

The SI unit of work is the joule (J), which is defined as the work done when a force of one newton is applied to an object that moves one meter in the direction of the force.

$$W=F\cdot d\cdot \ cos \ \theta$$

Where:

* W is work in joules (J)

* F is the magnitude of the force applied in newtons (N)

* d is the distance over which the force is applied in meters (m)

* θ is the angle between the force and the displacement

Work is a scalar quantity, which means that it has only magnitude and no direction. It is positive when the force and displacement are in the same direction, and negative when the force and displacement are in opposite directions.