# Work

The energy a force transfers when it moves something. Work is force times distance moved along the force, W = F d cos theta.

Physics (university) · Part 03: Work, energy and momentum · Card 1 of 9 · Last updated 2026-10-19

## Analogy

Pushing a car: no movement, no work, however tired you feel.

## Example

**Angled pull**

W = F d cos 60
W = 50 x 10 x 0.5
W = 250 J

## In practice

A 50 N pull at 60 degrees over 10 m does 250 J of work.

## Practice

### Flashcards

- **What is one joule?** The work done by a 1 N force over 1 m, equal to 1 kg m^2/s^2.

## Questions people ask

### Can a force do zero work?

Yes. If the object does not move, or if the force is at right angles to the motion, no work is done. A waiter carrying a tray at constant height does no work on the tray with the upward support force, because it is perpendicular to the motion.

### Can work be negative?

Yes. When a force points against the motion, it takes energy away from the object. Friction on a sliding box does negative work, which slows the box, and that work equals minus F times d. Negative work reduces kinetic energy, while positive work increases it.

## Related concepts

- [Kinetic energy](https://studyvisually.com/learn/science/physics-university/physics-university-part-3/physics-university-part-3-concept-2)
- [Work-energy theorem](https://studyvisually.com/learn/science/physics-university/physics-university-part-3/physics-university-part-3-concept-3)
- [Gravitational potential energy](https://studyvisually.com/learn/science/physics-university/physics-university-part-3/physics-university-part-3-concept-4)
- [Conservation of energy](https://studyvisually.com/learn/science/physics-university/physics-university-part-3/physics-university-part-3-concept-5)

Web page: https://studyvisually.com/learn/science/physics-university/physics-university-part-3/physics-university-part-3-concept-1
Study this card in the app: https://studyvisually.com/app/learn?category=physics-university&card=physics-university-part-3-concept-1