Physics 0625 · IGCSE · Energy, work and power

Energy, work and power — practice question

Blocks A and B are connected by a light thread that runs over a frictionless pulley. Block A is stationary on a rough horizontal surface, and block B is held stationary just below the pulley. Fig. 1.1 shows the thread hanging slack. The diagram labels: block A on a rough horizontal surface, a pulley, a thread, and block B hanging vertically. Block B is released and drops vertically. The thread remains slack until block B has fallen 0.45 m. Block B has a mass of 0.50 kg.
(a)[2]

Calculate the change in the gravitational potential energy (g.p.e.) of block B as it drops through 0.45 m.

(b(i))[3]

Calculate the impulse exerted on block A as it speeds up from rest to 0.60 m/s.

(b(ii))[3]

Both blocks now travel at a constant speed of 0.60 m/s until block B reaches the ground and the thread goes slack. Explain the energy change that occurs in block A after block B stops moving.

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