Practise Moments, levers and gears. 14 exam-style questions plus unlimited generated ones on this subtopic, at up to four difficulty levels, with full mark schemes and a progress tracker. Free, no account needed.
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Write down the equation that links distance (d), force (F) and moment of a force (M).
M = F d
State whether it is easier to crack the nut by placing it close to the hinge, or far from the hinge (near the handles).
Close to the hinge.
Sample questions
Written for this site in the style of AQA exam questions. They are not taken from real past papers.
Question 1Easy4 marks
(a) A force is applied further from the pivot of a lever, without changing its size. What happens to the moment of the force? Tick (✓) one box.[1]
It increases
It decreases
It stays the same
It becomes zero
(b) Which two of these are examples of a lever? Tick (✓) two boxes.[2]
A pair of scissors
A brick
A see-saw
A ball
(c) Write down the equation that links distance (d), force (F) and moment of a force (M).[1]
Show the answer and mark scheme
(a)Answer: It increases
(b)Answer: A pair of scissors; A see-saw
(c)Answer: M = F d
M = F d
Question 2Medium4 marks
A student uses a pair of nutcrackers to crack a nut. The nutcrackers act as a lever with the hinge at one end and the hands squeezing the handles at the other end.
(a) State whether it is easier to crack the nut by placing it close to the hinge, or far from the hinge (near the handles).[1]
(b) Explain your answer, using the idea of moments.[3]
Show the answer and mark scheme
(a)Answer: Close to the hinge.
close to the hinge
(b)Answer: The moment of the hands’ force about the hinge is the same; the nearer the nut is to the hinge, the smaller its distance, so the bigger the force on the nut (force = moment ÷ distance).
the hands apply the same moment about the hinge (same force at the same distance from the hinge)
the moment of the force between the nut and the nutcracker about the hinge must balance this moment, and moment = force × distance
so when the nut is closer to the hinge (smaller distance), the force on the nut is bigger for the same effort, making it easier to crack
Question 3Hard6 marks
A claw hammer is used to pull out a nail. The claw acts as a lever, pivoting on the wood, with the nail 2.0 cm from the pivot and the hand pulling perpendicular to the handle, 28 cm from the pivot.
(a) The hand applies a force of 45 N. Calculate the force acting on the nail.[3]
(b) As the nail is pulled out, the hand moves through a much bigger distance than the nail moves. Use the idea of work done to explain why the force on the nail (630 N) can be so much bigger than the force applied by the hand (45 N), even though a lever cannot create energy.[3]
Show the answer and mark scheme
(a)Answer: 630 N
moment about the pivot = 45 × 0.28 = 12.6 (N m)
12.6 = force on the nail × 0.02
force on the nail = 630 (N)
(b)Answer: Work done (force × distance) is the same at both ends; the hand moves much further than the nail, so the nail end can exert a much bigger force without creating any extra energy.
ignoring friction and other losses, the work done by the hand equals the work done on the nail: force × distance moved must be (about) the same at both ends of the lever
the hand end of the claw sweeps through a much bigger distance than the nail end, because it is much further from the pivot
so, for equal work done, the smaller distance moved by the nail allows a much bigger force to act there — the lever trades distance moved for force, it does not create energy