Pearson Edexcel International GCSE (9–1) · PHYSICS · Unit
Energy Resources and Energy Transfers
175 practice questions
Topics covered
Practice questions
81–90 of 175
Question 81
5 marks · Hard
Answer and see the solution →A passenger lift of mass 800 kg carries 5 people each of mass 60 kg to a height of 18 m in 22 s. Assume the upward force from the cables exactly balances the total weight as the lift moves at constant speed.
(a)[1 mark]Calculate the total weight lifted by the cables.
(b)[2 marks]Calculate the work done on the lift and passengers in raising them to the top floor.
(c)[2 marks]Calculate the power developed by the lift motor.
Question 82
4 marks · Hard
Answer and see the solution →A bungee jumper leaps from a bridge, attached securely to an elastic cord. Describe in detail how energy is transferred between stores from the moment the jumper steps off the platform until the lowest point of the jump, including where energy is not conserved as useful energy. Refer to named energy stores and describe at least three distinct transfers in your answer.
Question 83
5 marks · Hard
Answer and see the solution →A 0.25 kg ball is dropped from a balcony 25 m above the ground. Ignore air resistance.
(a)[2 marks]Calculate the gravitational potential energy lost by the ball as it falls.
(b)[2 marks]Determine the speed of the ball just before it hits the ground.
(c)[1 mark]Explain why, in real life, the ball’s speed might be less than your calculation.
Question 84
4 marks · Easy
Answer and see the solution →A worker pushes a trolley with a constant force of for a distance of along a straight corridor. The trolley and its load have a combined mass of .
(a)[2 marks]Calculate the work done on the trolley by the worker.
(b)[1 mark]State the energy store that increases as a result of this work being done.
(c)[1 mark]If the work is done in 12 seconds, calculate the power developed by the worker.
Question 85
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 86
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 87
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 88
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 89
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 90
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.