The formula
W = F · d
| Symbol | Quantity | Unit |
|---|---|---|
| W | Work | J |
| F | Force | N |
| d | Distance | m |
What it means
In physics, work has a narrow meaning: energy transferred by a force acting through a distance. Holding a heavy box still is exhausting and does no work at all, because nothing moves.
How to work it out by hand
- Take the force in newtons
- Multiply by the distance moved in metres
- Only the distance along the force counts
What is worth knowing
The 'in the direction of the force' clause is the one that matters. Carrying a suitcase along a level corridor does no work against gravity, because gravity pulls down and you move sideways — the two are perpendicular and the work is zero. Your muscles still burn energy holding it up, which is a biological cost rather than mechanical work, and that gap between the physics definition and the everyday one is why the term causes so much confusion. Work and energy share the joule as a unit precisely because work is energy transferred.