Moments, levers and gears
I can explain how levers and gears transmit the rotational effects of forces.
Moments, levers and gears
I can explain how levers and gears transmit the rotational effects of forces.
Lesson details
Key learning points
- A force can produce a turning effect known as a moment.
- If an object is in equilibrium, there is no resultant force or moment on it.
- moment = force × distance (M = Fd)
- Levers can act as force or distance multipliers.
- Gears can be used to transfer moments.
Common misconception
Pupils may think that a lever gives you ‘something for nothing’ when used as a force multiplier.
Ask a pupil to lift an object by a particular height (say 10 cm) without a pivot, then with a pivot and a plank as a lever to compare the effort and distance moved in each case.
Keywords
Equilibrium - The state of an object when there is no resultant force or moment acting on it.
Moment - The turning effect of a force, measured in newton metres (Nm).
Force multiplier - A type of lever that increases the size of an applied force.
Distance multiplier - A type of lever that increases the distance an applied force moves through.
Gears - Toothed wheels that rotate around an axle and are used to transfer moments.
Equipment
None required.
Licence
This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
Video
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Starter quiz
6 Questions
Exit quiz
6 Questions
equilibrium -
the state of an object if there is no resultant force or moment on it
moment -
the turning effect of a force, measured in newton metres (Nm)
force multiplier -
a lever that increases the size of an applied force
distance multiplier -
a lever that increases the distance an applied force moves through
gear -
a toothed wheel that rotates and is used to transfer a moment
