Work, Power & Energy ResourcesEdexcel IGCSE Physics: Subtopic test

1. 1
   A dockyard crane lifts a shipping container weighing 20,000 N vertically upwards through a distance of 8 m at a steady speed.

   (a)

   Which equation should be used to calculate the work done by the crane on the container?

   [1 mark]

   • Awork done = force × time taken
   • Bwork done = force ÷ distance moved in the direction of the force
   • Cwork done = force × distance moved in the direction of the force
   • Dwork done = mass × distance moved

   (b)

   What is the correct unit for the work done by the crane on the container?

   [1 mark]

   • Awatt (W)
   • Bnewton (N)
   • Cpascal (Pa)
   • Djoule (J)

   (c)

   Calculate the work done by the crane in lifting the container through the 8 m distance. Show your working and give the correct unit.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A skateboarder of mass 50 kg rolls down a smooth ramp from rest, converting gravitational potential energy into kinetic energy as she descends.

   (a)

   Which energy store decreases as the skateboarder moves down the ramp?

   [1 mark]

   • Akinetic energy store
   • Bchemical energy store
   • Cgravitational potential energy store
   • Delastic energy store

   (b)

   Which equation is used to calculate the kinetic energy of the skateboarder at the bottom of the ramp?

   [1 mark]

   • AKE = m × g × h
   • BKE = F × d
   • CKE = 1/2 × m × v^2
   • DKE = m × v

   (c)

   The skateboarder starts 3.2 m above the bottom of the ramp. Assuming all gravitational potential energy is transferred to kinetic energy and the gravitational field strength is 10 N/kg, calculate her speed at the bottom of the ramp.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A hydroelectric power station stores water in a reservoir on a hillside and releases it through pipes to turbines far below, where the falling water spins the turbines to generate electricity.

   (a)

   Describe the energy transfers that take place from the water in the reservoir to the electricity supplied to the grid.

   [3 marks]

   (b)

   The power station releases 5000 kg of water per second through a height of 40 m, with a gravitational field strength of 10 N/kg. Calculate the useful electrical power output of the station if the overall process is 75% efficient.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A national government is deciding how to expand its electricity generation capacity for the next 20 years. It is considering a mix of wind power, solar cells, fossil fuel power stations and nuclear power stations.

   (a)

   Describe the energy transfers involved in generating electricity from each of these four methods, explaining clearly how the input energy store is converted into electrical energy in each case.

   [6 marks]

   (b)

   Evaluate the advantages and disadvantages of using nuclear power compared with wind power for this country's large-scale electricity generation, considering reliability, environmental impact and cost.

   [6 marks]

   Total for question 4: 12 marks

End of questions