Energy Stores & Systems - exam practice
Energy Stores & Systems
Question 1 of 4
This question is about a bouncy ball, held at rest, 1.3m above the ground.
State the equation linking gravitational potential energy, mass, gravitational field strength, and height.
The mass of the ball is 40 g and is held 1.3 m above the ground.
Calculate the gravitational potential energy of the ball.
The gravitational field strength on Earth is 9.8 N/kg.
The ball is released and falls to the ground. State the kinetic energy of the ball just before it hits the ground.
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Calculate the speed of the ball just before it hits the ground.
Give your answer to 2 decimal places in m/s.
Describe how the student could measure the final speed of the ball, just before it hits the ground.
Using ideas about forces, explain why the measured value of speed is different to the calculated value.
This question is about energy stores and transfers.
A cyclist is cycling along a horizontal road at constant speed.
State the name of the energy store of the cyclist that is decreasing as they cycle.
The mass of the bicycle and the cyclist is 95 kg.
The cyclist is travelling at 11 m/s.
Calculate the kinetic energy of the cyclist and bicycle.
The cyclist sees an obstacle in the road and needs to stop quickly.
Describe the energy transfer that takes place between the brakes being applied and the bicycle coming to rest.
This question is about energy stores and transfers.
Match the description to the energy store that is changing.
A student stretches an elastic band before releasing it to fire across the room.
Which method of energy transfer takes place as the elastic band is being stretched?
The energy stored in the elastic band is transferred to the kinetic store of the elastic band when the student releases it.
State the law of conservation of energy.
The elastic band has a spring constant of 6 N/m and is stretched by 15 cm.
Calculate the energy stored in the elastic band.
The mass of the elastic band is 2 g.
Calculate the speed of the elastic band when it is released.
This question is about energy transfers and transfer mechanisms.
Which of the following is the useful energy store for a car?
Cars are not 100% efficient.
Which of the following is the wasted energy store for a car?
A car has 50 MJ of kinetic energy.
Which of the following is not the amount of work that needs to be done to bring the car to rest?
Burning some fuel releases 15 kJ of thermal energy. The car gains 9 kJ of useful energy from the fuel burned.
Calculate the efficiency of the car.