Question 41
HA winch is used to pull a box up a ramp onto the back of a lorry.
The Figure shows the box on the ramp.
Figure
The winch pulls the box up the whole length of the ramp with a constant force of 250 N parallel to the ramp.
The mass of the box is 40 kg.
The winch motor is supplied with 3000 J of energy as the box is pulled up the ramp.
Gravitational field strength (ggg) = 10 N/kg
a.[2]
Calculate the work done by the winch on the box.
b.[2]
Calculate the increase in gravitational potential energy of the box.
c.[2]
Calculate the efficiency of the winch motor.
d.[3]
Explain why the overall efficiency of raising the box, from the energy supplied to the winch motor to the gravitational potential energy store of the box, is lower than the efficiency of the winch motor.
Use your answers to (a), (b) and (c).
8.3 Power and efficiency Questions
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.