Energy Resources and Energy Transfers
4 marks · EasyA cyclist uses food energy to pedal up a hill. The food energy is measured in joules (J). Assume friction is small.
What unit is used to measure the cyclist's mass?
Name the energy store that increases when the cyclist is at the top of the hill.
Suggest why not all the energy supplied to the cyclist is transferred usefully.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) kilogram (kg)
(b) gravitational potential energy (GPE)
(c) Some energy is transferred to heat and sound, or lost through friction and air resistance. · must show Reference to heat/sound/friction
Common mistakes: Confusing GPE and kinetic energy in part b
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Correctly states 'kilogram' or 'kg' as the unit of mass.
B1 (b) · 1 mark · Correctly identifies gravitational potential energy as the increasing store at the top of the hill.
B1 (c) · 1 mark · States that some energy is transferred to heat, sound, friction or air resistance.
B1 (c) · 1 mark · Gives a reason, such as not all energy is transferred usefully.
Worked solution
a) Mass is measured in kilograms (kg).
b) The energy store that increases is gravitational potential energy (GPE).
c) Not all the energy is transferred usefully as some is transferred to heat and sound, or lost through friction and air resistance.