Practise Work done and energy transfer. 14 exam-style questions plus unlimited generated ones on this subtopic, at up to four difficulty levels, with full mark schemes and a progress tracker. Free, no account needed.
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A removal worker pushes a box 6.0 m along a corridor with a horizontal force of 150 N. Calculate the work done by the worker. Use the equation: work done = force × distance
900 J
Write down the equation that links distance (s), force (F) and work done (W).
W = F s
The lift took 1.4 s. Calculate the average useful power output of the weightlifter during the lift.
2100 W (2058 W) W
Write down the equation that links distance moved along the line of action of the force (s), force (F) and work done (W).
W = F s
Sample questions
Written for this site in the style of AQA exam questions. They are not taken from real past papers.
Question 1Easy5 marks
(a) A removal worker pushes a box 6.0 m along a corridor with a horizontal force of 150 N. Calculate the work done by the worker. Use the equation: work done = force × distance[2]
(b) Which unit is equivalent to the joule? Tick (✓) one box.[1]
N/m
N m
N/m2
kg m/s
(c) Friction acts between the box and the floor. What happens to the temperature of the box and the floor as the box is pushed?[1]
(d) Complete the sentence. When a force causes an object to move through a distance, ............ is done on the object.[1]
Show the answer and mark scheme
(a)Answer: 900 J
W = 150 × 6.0
900 (J)
(b)Answer: N m
(c)Answer: It increases.
it increases / they get warmer
(d)Answer: work
work
Question 2Medium7 marks
A crane lifts a steel beam of mass 850 kg vertically upwards through a height of 24 m at a constant speed. gravitational field strength = 9.8 N/kg
(a) Calculate the weight of the beam.[2]
(b) Calculate the work done by the crane on the beam. Give your answer in kilojoules.[3]
(c) Describe the energy transfer that takes place as the crane lifts the beam.[2]
Show the answer and mark scheme
(a)Answer: 8330 N
W = 850 × 9.8
8330 (N)
(b)Answer: 200 kJ (199.92 kJ) kJ
W = 8330 × 24
199 920 (J)
200 (kJ) / 199.92 (kJ)
(c)Answer: The crane does work on the beam, transferring energy to the beam’s gravitational potential energy store.
work is done on the beam by the (tension in the) cable / crane
energy is transferred to the gravitational potential energy store of the beam
Question 3Hard7 marks
A shop assistant lifts a box of mass 8.0 kg from the floor onto a shelf 1.5 m above the floor. gravitational field strength = 9.8 N/kg
(a) Calculate the work done on the box as it is lifted onto the shelf.[3]
(b) The assistant then carries the box 12 m across the shop, keeping it at the same height and moving at a constant speed. A student says: ‘The assistant does 78.4 × 12 = 941 J of work on the box while carrying it.’ Explain why the student is wrong.[2]
(c) The assistant then pushes a trolley 25 m across the shop. The assistant pushes on the handle at an angle to the horizontal. The horizontal component of the push is 48 N. Calculate the work done by the push.[2]
Show the answer and mark scheme
(a)Answer: 118 J (117.6 J) J
weight = 8.0 × 9.8 = 78.4 (N)
W = 78.4 × 1.5
118 (J) / 117.6 (J)
(b)Answer: The upward force is perpendicular to the horizontal motion, so the box moves no distance along the line of action of the force and no work is done by it.
the upward force on the box is at right angles to its (horizontal) movement / the box does not move in the direction of the upward force
so the distance moved along the line of action of the force is zero / no work is done by this force / the gravitational potential energy of the box does not change