Evaluate — 4 marks
A theme park is designing a new roller coaster. Engineers must choose between two braking systems for the final descent: System A uses friction brake pads that convert kinetic energy directly to heat, while System B uses regenerative electromagnetic brakes that convert kinetic energy into electrical energy stored in a battery. Both systems must safely stop a 500 kg carriage travelling at 20 m/s within 50 m.
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Calculate the kinetic energy of the carriage before braking begins.
[1 mark]
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System A converts all kinetic energy to thermal energy in the brake pads. Explain why this system might be considered wasteful from an energy conservation perspective.
[1 mark]
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Evaluate the advantages and disadvantages of System B (regenerative braking) compared to System A for use on a theme park roller coaster. Consider both energy efficiency and practical factors.
[2 marks]
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Show — 2 marks
A student drops a rubber ball from a height of 2 metres onto a hard floor. The ball bounces back up to a height of 1.5 metres. Some energy is lost during the collision with the floor.
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Show that the ball loses gravitational potential energy as it falls from 2 m to the floor.
[1 mark]
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Explain why the ball does not bounce back to its original height of 2 metres.
[1 mark]
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Calculate — 2 marks
A student investigates the energy transfers in a filament lamp. The lamp is switched on for one minute. During this time, 3000 J of electrical energy is supplied to the lamp. Of this energy, 2700 J is transferred to the surroundings as thermal energy.
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(01.1) Calculate the amount of useful light energy transferred by the lamp.
[1 mark]
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(01.2) Calculate the efficiency of the lamp.
[1 mark]
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- (01.1) 300 (J) or 3000 – 2700
- (01.2) 10% or 0.1 or correct calculation using their answer from 01.1
Explain — 3 marks
A student drops a basketball from a height of 1 metre. The ball bounces on the floor several times, with each bounce lower than the one before. Eventually, the ball stops moving.
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(01.1) State the main energy store of the ball just before it is released.
[1 mark]
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(01.2) Explain why the ball does not bounce back up to its original height of 1 metre.
[2 marks]
Show mark scheme
- (01.1) Gravitational potential energy (store)
- (01.2) Energy is transferred to the surroundings / thermal energy store (of ball, floor, air)
- (01.2) Energy is also transferred to the sound energy store / dissipated
Describe — 2 marks
A student drops a rubber ball onto a hard floor. The ball bounces several times, with each bounce reaching a lower height than the previous one, until the ball eventually comes to rest on the floor.
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(01.1) Describe what happens to the total kinetic and potential energy of the ball after each bounce.
[1 mark]
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(01.2) Describe what happens to the energy that is 'lost' from the ball as it bounces.
[1 mark]
Show mark scheme
- (01.1) Total kinetic and potential energy decreases (after each bounce)
- (01.2) Dissipated/transferred to surroundings as thermal energy/heat
- (01.2) OR dissipated/transferred to surroundings as sound
GCSE Perfect