Work

Definition

Work is the energy transferred to or from an object via the application of force along a displacement. It is mathematically defined as the dot product of force and displacement vectors.

5 Must Know Facts For Your Next Test

1. Work is calculated using the formula $W = \vec{F} \cdot \vec{d}$, where $\vec{F}$ is the force and $\vec{d}$ is the displacement.
2. The SI unit for work is the joule (J), where 1 joule equals 1 newton-meter.
3. If the angle between the force and displacement vectors is 90 degrees, no work is done because $\cos(90^\circ) = 0$.
4. Positive work occurs when the force component in the direction of displacement does positive work, and negative work occurs when it does negative work.
5. In a conservative force field, such as gravity, work done by conservative forces depends only on initial and final positions, not on the specific path taken.

Review Questions

• What happens to the work done if the displacement vector is perpendicular to the applied force?
• How do you calculate work when given a varying force over a specific distance?
• What distinguishes positive work from negative work in physical terms?

Related terms

Kinetic Energy:

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

Potential Energy:

The energy stored in an object due to its position or configuration, such as gravitational potential energy which depends on height.

Power:

The rate at which work is done or energy is transferred, measured in watts (W), with 1 watt equal to 1 joule per second.