IGCSE 0625 / Section 1.7 / Core

Work is energy on the move.

Pushing a stalled car, lifting a crate, dragging a sledge: whenever a force shifts something along its own direction, it does work, and that work is exactly the energy it hands over. No movement in the direction of the force means no work, no matter how hard you push.

The key idea

Work done = force × distance moved in the direction of the force: W = Fd, measured in joules. The work done is equal to the energy transferred. The force must act along the direction of motion for it to do work.

Definition · learn the exact words

Work done is the force multiplied by the distance moved in the direction of the force.

W = F d  (unit: joule, J)

The work done by a force is equal to the energy transferred.

Section 01

Push along, and transfer energy.

Set the force and the distance, then push the load. The work done, shown as the shaded area, is the force multiplied by the distance moved in the direction of that force.

Stage 1 · Learn

Check work and energy

Four quick checks on W = Fd, its unit, and the energy link. Each correct answer earns XP and lights this skill on your star map.

Quick check+10 XP

Work done is calculated as...

Quick check+10 XP

Work done is measured in...

Quick check+10 XP

The work done by a force is equal to...

Quick check+10 XP

If a force acts at right angles to the motion, the work it does is...

Section 02

Force, distance, direction.

The defining equation:

W = F d  (force in N, distance in m, work in J)
Worked example

A 25 N force drags a crate 6.0 m across the floor in the direction of the force. Find the work done.

Step 1 · Write the equationW = F d
Step 2 · SubstituteW = 25 × 6.0 = 150 J
Step 3 · AnswerThe work done is 150 J, which is the energy transferred to the crate and its surroundings.
Examiner trap

A force at right angles to the motion does no work. When you carry a bag along a level floor, the upward force you apply is vertical while the motion is horizontal, so that force transfers no energy. Only a force with a component along the direction of motion does work.

Stage 2 · Exam

Exam-style questions

Unlocks once the four checks above are done. Worth more XP, written in the style of Paper 2.

Finish the four checks above to unlock the exam questions
Exam style+20 XP

A force of 20 N pushes a box 3.0 m in the direction of the force. The work done is...

Exam style+20 XP

A crane does 4000 J of work lifting a load through 8.0 m. The lifting force is...

Exam style+20 XP

A waiter carries a tray horizontally across a level room at steady speed. The work done by the upward force supporting the tray is...

Skill unlocked

Work done, mastered.

This skill is now lit gold on your star map. Keep the chain going.

-Rank -Level -Score -Topics
Go deeper · practice
Six original Cambridge-style questions
The W = Fd relationship, its unit, rearranging for force or distance, the link to energy transferred, and the perpendicular-force case. Attempt each, then reveal the worked solution.
Stage 3 · master the unit
Motion, forces and energy challenge
Mixed questions across the whole unit, each one worth XP. Start this only when you feel confident across every topic in the unit, not just work done.
Start the unit challenge →