Pearson Edexcel International GCSE (9–1) · PHYSICS · Section
Power
18 practice questions
Practice questions
1–8 of 8 · Normal
Question 1
4 marks · Normal
Answer and see the solution →A small electric motor raises a 2.0 kg mass vertically upwards a distance of 8.0 m in 6.0 s.
(a)[2 marks]Calculate the work done by the motor in raising the mass.
(b)[2 marks]Calculate the power output of the motor during this time.
Question 2
2 marks · Normal
Answer and see the solution →Explain why, as a rollercoaster descends from the highest point to the lowest, its gravitational potential energy decreases while its kinetic energy increases.
Question 3
1 mark · Normal
Answer and check →Which statement best describes the unit of power?
- A.One joule transferred per second
- B.One newton per second
- C.One metre per second
- D.One kilogram per second
Question 4
3 marks · Normal
Answer and see the solution →A lift with passengers has a combined weight of 3500 N. The lift rises vertically at a constant speed of 2.5 m/s.
(a)[1 mark]State the upward force needed to keep the lift moving at constant speed.
(b)[2 marks]Calculate the power output of the lift motor.
Question 5
1 mark · Normal
Answer and see the solution →State the formula relating power, work done (or energy transferred), and time.
Question 6
3 marks · Normal
Answer and see the solution →A student with a mass of 60 kg runs up a flight of stairs in 9.0 s. The stairs have 12 steps, each 0.25 m high. Use g = 10 N/kg.
Question 7
3 marks · Normal
Answer and see the solution →A cyclist rides up a hill at a constant speed. Explain, using ideas about energy stores and transfers, why the cyclist must keep pedalling to maintain this speed.
Question 8
3 marks · Normal
Answer and see the solution →A table shows the time taken for four students to lift identical boxes through the same vertical distance:
Student Time taken (s) Ali 10 Ben 8 Chloe 12 Dina 6 Each box requires 300 J of work to be lifted.
(a)[1 mark]Which student had the greatest power output?
(b)[2 marks]Calculate the power output for this student.