Energy transfers.

The cyclist rides from a flat road to the top of a hill. The cyclist returns to the flat road. The cyclist then uses the brakes on the bicycle to stop. Explain what happens to the kinetic energy of the cyclist when the brake is applied. (2)

The kinetic energy decreases (1) and thermal energy increases (1)

Figure 5 shows a way of projecting a small trolley up a sloping track. When the button is pressed, a spring is released in P that projects the trolley up the track. The trolley travels up the track, stops and then rolls back down. The spring in P always exerts the same force when projecting the trolley. A student investigates how the mass of the trolley affects the maximum vertical height, h, reached by the trolley. State the measurements the student should make to complete the investigation. You should make use of the equipment shown in Figure 5 and any other equipment that is needed. (4)

measure mass of the trolley (1) measure the vertical height (1) repeat for a range of masses (1)repeat firing with same mass (1)

Figure 11 shows a wind turbine. Explain how unwanted energy transfers could be reduced in the gear box. (2)

Use of lubrication (1) to reduce friction (1)

Describe an energy transfer that occurs when the student lifts the toy car from the bench and places the toy car at the top of the slope. (2)

Chemical energy in the students’ muscle is transferred mechanically to the GPE of the toy car.

Before a car brakes it has kinetic energy. The kinetic energy decreases as it brakes. State what happens to the kinetic energy during braking. (1)

causes heating of the surroundings (1)