IGCSE Physics Work Questions and Worked Solutions
50 topic-wise practice questions on Work (Unit 1: Motion, Forces and Energy), written to the Cambridge IGCSE Physics 0625 syllabus for 2026–2028, each with a step-by-step worked solution.
Topic guide: Work
Work is done when a force moves an object through a distance. The work done equals the energy transferred, so work and energy share the same unit, the joule.
Key formulas
| W = F d | work done W (J), force F (N), distance moved in direction of force d (m) | Core |
| work done = energy transferred | 1 J = 1 N m | Core |
Prerequisite knowledge
- Forces (1.5.1)
- Energy stores and transfers (1.7.1)
Exam tips & common mistakes
- Use the distance moved IN THE DIRECTION of the force
- Convert km to m and kN to N
- Holding a heavy object still does no work on it
Key facts from the syllabus (1.7.2)
- Mechanical work is done by a force moving through a distance; electrical work is done by a current
- If there is no movement in the direction of the force, no work is done
- Work done against friction transfers energy to the internal (thermal) store
- Work done lifting an object = weight × height = gain in gravitational potential energy
- Braking work = kinetic energy lost
Textbook: §1.7 Energy, work and power, pp. 60–77
State the relationship between work done and energy transferred.
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Method: They are equal.
State the equation for mechanical work done.
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Method: W = Fd.
A force of 40 N pushes a box 3.0 m along the floor. Calculate the work done.
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Method: W = Fd.
A crane lifts a 2000 N load 15 m. Calculate the work done on the load.
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Method: W = Fd.
110 J of work is done pulling a bow string back 0.45 m. Calculate the average force.
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Method: F = W ÷ d.
A student does 600 J of work pushing a trolley with a force of 150 N. Calculate the distance moved.
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Method: d = W ÷ F.
State the unit of work.
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Method: Same as energy.
A person holds a heavy box still. Explain why no mechanical work is done on the box.
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Method: No distance moved.
A 65 kg student climbs stairs of vertical height 3.5 m. Calculate the work done against gravity (g = 9.8 N/kg).
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Method: W = weight × height.
Explain why a cyclist does work against friction when riding at constant speed.
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Method: Friction/drag act against motion over a distance.
A lift does 54 000 J of work raising people 12 m. Calculate the force it exerted.
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Method: F = W ÷ d.
Calculate the work done when a 7.5 N force moves an object 80 cm.
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Method: Convert cm to m.
State the energy transfer when work is done pushing a block across a rough floor at constant speed.
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Method: Friction heats surfaces.
A car engine provides a driving force of 3000 N over 2.5 km. Calculate the work done in MJ.
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Method: W = Fd with d = 2500 m.
A force is perpendicular to the direction of motion. State the work done by this force.
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Method: No distance in the direction of the force.
A weightlifter raises a 1500 N bar by 2.0 m. Calculate the energy transferred to the bar's gravitational potential store.
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Method: W = Fd = ΔE.
Electrical work of 1800 J is done by a motor. State the total energy transferred by the motor.
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Method: Work done = energy transferred.
A 20 N force pulls a sledge 15 m, and friction is 20 N. Calculate the work done against friction.
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Method: W = Ffriction × d.
A bow is pulled back with an average force of 240 N through 0.45 m. Calculate the work done.
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Method: W = Fd.
A box is pushed 6.0 m with a force of 50 N, then 4.0 m with 30 N. Calculate the total work done.
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Method: Add the two amounts.
A 25 N force moves a sledge 12 m. Calculate the work done.
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Method: W = Fd.
A person does 2400 J of work pushing a car 8.0 m. Calculate the average force.
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Method: F = W ÷ d.
A lift motor does 36 000 J of work with a force of 6000 N. Calculate the height raised.
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Method: d = W ÷ F.
A 50 kg box is lifted 1.2 m onto a shelf (g = 9.8 N/kg). Calculate the work done.
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Method: W = mgh.
State what happens to the energy when work is done against friction.
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Method: Thermal.
A trolley is pulled with a force of 15 N for 4.0 m, then 10 N for 6.0 m. Calculate the total work done.
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Method: Sum.
Calculate the work done when a 0.50 N force moves through 40 cm.
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Method: Convert cm to m.
State the work done by gravity on a satellite moving in a circular orbit at constant height.
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Method: Force perpendicular to motion.
A car brakes with a force of 6000 N and stops in 25 m. Calculate the work done by the brakes.
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Method: W = Fd.
A car of mass 1200 kg moving at 20 m/s brakes to rest. Using energy, calculate the work done by the brakes.
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Method: Work = Ek lost.
For the car in the previous question, the braking force is 8000 N. Calculate the braking distance.
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Method: d = W ÷ F.
Explain why a cyclist going uphill at constant speed does more work than on the flat.
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Method: Against gravity too.
State the name of the unit equal to 1 N m of work.
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Method: Joule.
Express 1 joule in terms of newtons and metres.
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Method: W = Fd.
A crane lifts a 12 kN load through 25 m. Calculate the work done in kJ.
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Method: W = Fd.
A child pulls a toy 5.0 m with a 4.0 N force; the toy speeds up. State whether all the work increases the toy's kinetic energy.
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Method: Friction.
A 60 kg climber climbs a 300 m hill (g = 9.8 N/kg). Calculate the work done against gravity in kJ.
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Method: W = mgh.
A student pushes against a wall with a force of 200 N for 30 s. State the work done on the wall and explain.
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Method: No movement.
A box is dragged 8.0 m across a floor with a horizontal force of 45 N at constant speed. State the friction force and calculate the work done against friction.
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Method: Constant speed: balanced.
An electric motor lifts a 30 N weight through 2.0 m. Calculate the useful work done.
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Method: W = Fd.
Challenge questions
Harder, multi-step questions at the top end of the exam. Attempt these once you are confident with the questions above.
A man pushes a 40 kg crate 12 m up a ramp, raising it 3.0 m. He pushes with 140 N along the ramp. Calculate (a) work done by the man, (b) gain in GPE (g = 9.8 N/kg), (c) work done against friction.
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Method: W = Fd; Ep = mgh.
A car of mass 1000 kg moving at 20 m/s brakes to rest. The brakes do 160 000 J of work and the rest is done by air resistance and rolling friction. Calculate the work done by other resistive forces.
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Method: Ek lost = total work.
A crane lifts a 2.0 t load at constant speed through 18 m (g = 9.8 N/kg). The motor uses 600 kJ. Calculate the useful work and the efficiency.
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Method: W = mgh.
A box is pushed 5.0 m across a floor at constant speed against 60 N of friction, then lifted 1.2 m onto a table (weight 150 N). Calculate the total work done.
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Method: Add.
A 70 kg cyclist (including bike) freewheels down a hill dropping 15 m and reaches the bottom at 12 m/s from rest. Calculate the work done against resistive forces (g = 9.8 N/kg).
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Method: Ep − Ek.
A force–distance graph for stretching a bow rises steadily from 0 N to 300 N over 0.50 m. Calculate the work done (area under the graph).
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Method: Area of triangle.
Explain why a satellite in a circular orbit has no work done on it by gravity, although gravity acts on it all the time.
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Method: Force perpendicular to motion.
A 60 kg student does 20 pull-ups, raising their body 0.45 m each time, in 1.0 minute. Calculate the total work done against gravity and the average power.
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Method: W = mgh × 20.
A train's engine provides 50 kN for 2.0 km while the train travels at constant speed. State the total resistive force and calculate the work done against it.
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Method: Constant speed: balanced.
Two people move identical boxes onto a 1.0 m high truck. One lifts vertically; the other pushes up a frictionless 4.0 m ramp. Compare the work done and the force needed.
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Method: Same Ep gain.
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