Work and Power
4 marks · EasyA worker pushes a trolley with a constant force of for a distance of along a straight corridor. The trolley and its load have a combined mass of .
Calculate the work done on the trolley by the worker.
State the energy store that increases as a result of this work being done.
If the work is done in 12 seconds, calculate the power developed by the worker.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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(a) 960 J
(b) Kinetic energy (movement energy)
(c) 80 W
Common mistakes: Forgets to use correct units; Incorrect formula rearrangement
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Marking points
M1 (a) · 1 mark · Writes or uses correct equation: work = force × distance.
A1 (a) · 1 mark · Substitutes and calculates work correctly: 120 N × 8 m = 960 J.
B1 (b) · 1 mark · States energy store: kinetic energy (accept: movement energy).
A2 (c) · 1 mark · Calculates power: 960 J ÷ 12 s = 80 W. (follow-through)
Worked solution
a) Work done = force × distance
b) The trolley's kinetic energy (energy of movement) increases.
c) Power = work done ÷ time