Pearson Edexcel International GCSE (9–1) · PHYSICS · Chapter
Work and Power
58 practice questions
Topics covered
Practice questions
51–58 of 58
Question 51
5 marks · Easy
Answer and see the solution →A box of mass is lifted from the ground onto a platform high. It is then pushed horizontally for along the platform with a force of .
(a)[2 marks]Calculate the work done to lift the box onto the platform.
(b)[1 mark]Calculate the increase in gravitational potential energy (GPE) of the box after lifting.
(c)[1 mark]Calculate the work done in moving the box horizontally on the platform.
(d)[1 mark]Name the type of energy store that increases as the box is pushed along the platform.
Question 52
4 marks · Easy
Answer and see the solution →A cyclist with mass is riding at a speed of . The cyclist and bicycle come to rest after applying the brakes, stopping over a distance of .
(a)[2 marks]Calculate the initial kinetic energy of the cyclist and bicycle.
(b)[1 mark]State what happens to this kinetic energy as the cyclist comes to rest.
(c)[1 mark]Calculate the average braking force exerted on the cyclist and bicycle to bring them to rest.
Question 53
4 marks · Easy
Answer and see the solution →A small elevator with total weight rises vertically in at a constant speed.
(a)[1 mark]Calculate the work done by the elevator motor to raise the elevator.
(b)[1 mark]State the increase in gravitational potential energy (GPE) of the elevator.
(c)[2 marks]Calculate the power output of the elevator motor during the lift.
Question 54
6 marks · Normal
Answer and see the solution →A construction worker lifts a toolbox of mass 12 kg vertically upwards at a steady speed through a height of 2.5 m in 5 seconds.
(a)[2 marks]Calculate the work done by the worker in lifting the toolbox.
(b)[1 mark]State the relationship between work done and energy transferred in this process.
(c)[3 marks]Calculate the power output of the worker while lifting the box.
Question 55
5 marks · Normal
Answer and see the solution →A diver of mass 60 kg jumps from a diving board 8 m above a swimming pool. Ignore air resistance.
(a)[2 marks]Calculate the gravitational potential energy (GPE) that the diver has at the top of the jump, relative to the water.
(b)[3 marks]Assuming all of the GPE is converted to kinetic energy (KE), calculate the speed of the diver just before hitting the water.
Question 56
5 marks · Normal
Answer and see the solution →A small electric cart has a mass of 120 kg and moves at a steady speed of 5 m/s along a horizontal track for 40 m. The total frictional force opposing its motion is 90 N.
(a)[2 marks]Calculate the work done against friction as the cart moves 40 m.
(b)[2 marks]Calculate the kinetic energy of the cart as it moves.
(c)[1 mark]State whether the work done against friction is equal to, less than, or greater than the kinetic energy of the cart. Explain your answer.
Question 57
5 marks · Normal
Answer and see the solution →A 400 kg rollercoaster car starts from rest at the top of a track 15 m above the ground. The car descends to the lowest point with negligible friction. Use g = 10 N/kg.
(a)[2 marks]Calculate the gravitational potential energy of the car at the top of the track.
(b)[3 marks]Calculate the speed of the car at the lowest point, assuming all the potential energy changes to kinetic energy.
Question 58
6 marks · Normal
Answer and see the solution →A student with weight 500 N runs up a set of stairs 4 m high in 10 s.
(a)[2 marks]Calculate the work done against gravity as the student climbs the stairs.
(b)[2 marks]Calculate the student's power output while running up the stairs.
(c)[2 marks]Describe one reason why the actual useful power output of the student might be less than the calculated value.