During a rehearsal, an electric winch in a theatre raises the same piece of scenery through the same height six times. The winch is 80% efficient and transfers a total of 1440 J usefully during the six lifts.
How much energy is supplied to the winch for each lift?
1800 J1800\ \mathrm{J}1800 J
192 J192\ \mathrm{J}192 J
240 J240\ \mathrm{J}240 J
300 J300\ \mathrm{J}300 J
100 exam-style questions on Edexcel GCSE Physics 3.2 Dissipation and efficiency, covering 3.2.1 Dissipation of energy, 3.2.2 Reducing unwanted energy transfers, 3.2.3 Efficiency, and 3.2.4 Increasing efficiency. Each one has a worked solution and a mark scheme showing where the marks go.