A window cleaner uses a motorized cradle to reach a window. The motor takes 6.3 s6.3\text{ s}6.3 s to lift the window cleaner and their equipment, which have a combined mass of 80 kg80\text{ kg}80 kg, a vertical height of 4.5 m4.5\text{ m}4.5 m. The power supplied to the cradle by its electric motor is 1.6 kW1.6\text{ kW}1.6 kW. What is the efficiency of the motorized cradle? (Take g=9.8 m/s2g = 9.8\text{ m/s}^2g=9.8 m/s2)
229 exam-style questions on CIE IGCSE Physics 1.7.1a Energy stores and energy transfers. Each one has a worked solution and a mark scheme showing where the marks go.