GCSE Physics Energy stores questions by topic

Name the energy store that is filling in each situation.

1. (a)A sprinter accelerates out of the blocks.[1]
2. (b)A hot water bottle cools a bed down overnight.[1]
3. (c)A stretched catapult band is released.[1]

State the principle of conservation of energy and use it to explain what happens to the “lost” energy of a bouncing ball.

1. (a)State the principle.[1]
2. (b)Explain where the energy goes between bounces.[2]

A hair dryer is labelled 1 200 W, 230 V and is used for 5 minutes.

1. (a)Calculate the energy transferred in 5 minutes, in joules.[2]
2. (b)State what happens to the energy that is not useful.[1]
3. (c)Name one useful energy transfer in the hair dryer.[1]

Complete the sentences about insulation.

1. (a)Lubrication reduces the size of the … store gained by moving parts.[1]
2. (b)Loft insulation is effective because the trapped air is a poor …[1]
3. (c)Double glazing has a … of gas between the panes.[1]
4. (d)A thicker wall transfers heat … quickly.[1]

Calculate the missing quantity in each row.

1. (a)Kinetic energy of the trolley.[1]
2. (b)Kinetic energy of the van.[1]
3. (c)Speed of the runner.[2]
4. (d)State the unit of speed used in the equation.[1]

A 2.0 kW electric kettle contains 1.5 kg of water at 18 °C (c of water = 4 200 J/kg °C).

1. (a)Calculate the energy needed to raise the water to 98 °C.[3]
2. (b)Calculate the minimum time the kettle takes.[2]
3. (c)Explain why the kettle takes longer than your answer to (b).[2]

An electric motor lifts a 400 N load through 6.0 m in 8.0 s. The motor draws 500 W from the supply.

1. (a)Calculate the useful work done lifting the load.[2]
2. (b)Calculate the useful power output.[2]
3. (c)Calculate the motor’s efficiency.[2]
4. (d)State what happens to the wasted power.[1]

Explain how each design feature reduces unwanted energy transfers in a house.

1. (a)Loft insulation 30 cm deep.[2]
2. (b)Double glazing with argon between the panes.[2]
3. (c)Foil backing behind a radiator.[2]

A roller-coaster car and passengers (total mass 800 kg) are dragged to the top of a 32 m drop. Ignore friction. (g = 9.8 N/kg)

1. (a)Calculate the gravitational potential energy at the top.[2]
2. (b)Calculate the speed at the bottom if all the g.p.e. transfers to kinetic energy.[3]
3. (c)State one way the real speed at the bottom differs from your answer, and why.[1]

A factory compares two machines. Machine A: input 4.0 kW, useful output 2.6 kW. Machine B: input 5.0 kW, useful output 3.5 kW.

1. (a)Calculate each machine’s efficiency.[4]
2. (b)Recommend one machine for the factory and justify the choice.[2]

This question is about the required practical for measuring specific heat capacity.

1. (a)Describe how a 1.0 kg aluminium block, a 12 V heater, a joulemeter and a thermometer are used to find c.[4]
2. (b)State the independent, dependent and one control variable.[3]
3. (c)The joulemeter reads 9 000 J and the temperature rises from 19 °C to 37 °C. Calculate c.[1]

A student says: “A more powerful machine must also be the more efficient one.”

1. (a)Explain the error in the student’s statement.[2]
2. (b)Support your explanation with a numerical example of two machines.[3]
3. (c)Name one design change that raises the efficiency of an electric motor.[1]

A 1 200 kg car travelling at 25 m/s brakes to a stop. All the kinetic energy transfers to the thermal store of the brakes.

1. (a)Calculate the kinetic energy transferred.[2]
2. (b)The four brake discs have a combined mass of 6.0 kg and warm by 100 °C. Calculate c for the disc material.[2]
3. (c)Explain why the discs reach a temperature only 100 °C higher, even though more energy than your (b) figure was transferred.[2]
4. (d)State one safety consequence of brakes that overheat.[1]

A student measures the specific heat capacity of water with a 50 W immersion heater, a polystyrene cup and a thermometer. The 0.80 kg of water warms from 20 °C to 34 °C in 100 s. The accepted value is 4 200 J/kg °C.

1. (a)Calculate the energy supplied and the measured c.[3]
2. (b)Calculate the percentage difference from the accepted value.[2]
3. (c)Explain the direction of the error and suggest one improvement.[3]