Physics - Energy

The actual maximum height reached by a pod with bungee cords will be lower than a calculated answer. Explain why. (2)

● Air resistance

● Not all of the elastic potential energy will be transferred to gravitational potential energy

Compare the advantages and disadvantages of the two methods of storing energy. Include calculations in your answer. (4)

● Heated water needs insulating

● Efficiency is 60%

● Suitable location needed to pump water uphill

● Efficiency is 75%

Explain one change that would reduce the amount of carbon dioxide released by each activity: Transport. (2)

● Don’t use cars for transport

● Use a bicycle/walk

Explain one change that would reduce the amount of carbon dioxide released by each activity: Generating electricity. (2)

● Don’t use fossil fuels

● Instead use renewable power

On one day the demand for electricity in the UK was 34,000 MW. Suggest two reasons why wind power was not able to meet this demand. (2)

● Wind is unreliable

● Not enough wind turbines in the UK

Some of the energy from the wind used to rotate a wind turbine is wasted. An engineer oils the mechanical parts of a wind turbine. Explain how oiling would affect the efficiency of the wind turbine. (3)

● The efficiency would increase

● As the percentage of energy wasted would decrease

● Less work is done against friction

Describe the energy changes involved when a ball is thrown upwards and then returns to it’s starting place. Ignore air resistance. (3)

● Upwards: KE is decreased, converts to GPE

● Peak height: GPE is maximum, no KE

● Downwards: GPE decreases as it is converted into KE