Work

Definition

Work is the transfer of energy that occurs when a force is applied to an object over a distance. It is calculated as the product of the force and the displacement in the direction of the force.

5 Must Know Facts For Your Next Test

1. The formula for work is $W = F \cdot d \cdot \cos(\theta)$, where $W$ is work, $F$ is force, $d$ is displacement, and $\theta$ is the angle between the force and displacement vectors.
2. Work is measured in joules (J), which are equivalent to newton-meters (N·m).
3. If the displacement of an object is zero, no work is done regardless of the amount of force applied.
4. When force and displacement are perpendicular ($\theta = 90^\circ$), no work is done because $\cos(90^\circ) = 0$.
5. Positive work occurs when the force has a component in the direction of displacement; negative work occurs when it has a component opposite to the direction of displacement.

Review Questions

• What are the units used to measure work?
• How does the angle between force and displacement affect the calculation of work?
• Is any work done if an object does not move? Explain.

Related terms

Energy:

The capacity to do work or produce heat; exists in various forms such as kinetic, potential, thermal, etc.

Kinetic Energy:

The energy possessed by an object due to its motion. Calculated as $KE = \frac{1}{2}mv^2$, where $m$ is mass and $v$ is velocity.

Potential Energy:

The energy stored in an object due to its position or configuration. Gravitational potential energy near Earth's surface can be calculated as $PE = mgh$, where $m$ is mass, $g$ is acceleration due to gravity, and $h$ is height.