Starter quiz
- Which of the following are the unit of force and its symbol?
- newtons ✓
- neutrons
- n
- N ✓
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- An object is __________ if no resultant force acts on it.
- speeding up
- in equilibrium ✓
- changing direction
- decelerating
-
What is the resultant force acting on the parachutist?- 200 N upwards ✓
- 200 N downwards
- 1900 N upwards
- 1900 N downwards
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- Which of the following conditions is required for an object to be in equilibrium?
- There are no forces acting on the object.
- There is an even number of forces acting on the object.
- The vector sum of the forces acting on the object is zero. ✓
- The forces acting on the object are all in equal and opposite pairs.
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- When an object rotates in the same direction as the hands on a clock, the direction of rotation is called ______.
- 'clockwise' ✓
- When an object rotates in the opposite direction as the hands on a clock, the direction of rotation is called ______.
- 'anticlockwise' ✓
Exit quiz
- Match the following key terms to their definition.
- 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 ✓
In how many of the following situations is the box in equilibrium?- 0 ✓
- 1
- 2
- 3
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- A lever can be a force multiplier or a distance multiplier. Which of the following levers is a distance multiplier?
What is the moment about the pivot caused by the force in the following diagram?- 40 Nm clockwise
- 40 Nm anticlockwise
- 1.6 Nm clockwise
- 1.6 Nm anticlockwise ✓
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What is the moment caused by the force about the pivot in the following diagram? You need to choose the correct distance for your calculation.- 33 Nm
- 39 Nm ✓
- 54 Nm
- 58 Nm
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The diagram shows a set of gears, X and Y, in a machine. Using an attached handle, a person produces a moment of 18 Nm about gear X, which rotates once. Which of the following statements are correct?- Gear Y makes 3 rotations. ✓
- Gear Y makes of a rotation.
- The moment of gear Y is Nm. ✓
- The moment of gear Y is 18 Nm.
- The moment of gear Y is 36 Nm.
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Worksheet
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Presentation
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Video
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.
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