Two identical steel girders are to be placed on the roof of a building 12 m above the…
PHYSICS · Multi-part · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
Two identical steel girders are to be placed on the roof of a building 12 m above the ground. Crane A needs 25 s to raise one girder, while Crane B needs 40 s for the same task.
Answer the following questions based on this situation.
(i) State what is meant by (a) work and (b) power in physics.
(ii) Explain, without using any formula in your answer, why both cranes do the same amount of work for one girder even though they take different times.
(iii) Explain clearly which crane is more powerful and why.
(iv) If each crane raises a second girder in the same manner, compare the total work done and the total power output of each crane for lifting two girders.