A motor lifts a load at constant speed. Its input power and efficiency remain constant. The mass of the load is doubled and the vertical distance is halved. How do the useful work done and the time taken compare with their original values?
The work is doubled and the time is unchanged.
The work is unchanged and the time is unchanged.
The work is doubled and the time is doubled.
The work is unchanged and the time is doubled.
128 exam-style questions on Edexcel GCSE Physics 8.3 Power and efficiency, covering 8.3.1 Power and 8.3.2 Efficiency. Each one has a worked solution and a mark scheme showing where the marks go.