A cable car of mass 1500 kg is pulled up a ski slope at a constant speed of 3.6 m s-1 by an electric winch. The slope is inclined at an angle θ \theta\,θ to the horizontal, where sinθ=0.08\sin\theta = 0.08sinθ=0.08. The motion of the cable car is opposed by a constant resistive force of 324 N. Given that the electrical power input to the winch motor is 7.5 kW, find the efficiency of the winch system. Take g=9.8 m s−2g = 9.8\text{ m s}^{-2}g=9.8 m s−2.
0.720.720.72
0.560.560.56
0.160.160.16
0.410.410.41
37 exam-style questions on OCR GCSE Physics Power and efficiency. Each one has a worked solution and a mark scheme showing where the marks go.