Mechanisms: levers, pulleys and gears

How simple machines like levers, pulleys and gears help us do work with less effort

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1
Label the parts of this simple pulley: wheel, rope, load.
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2
True or false? Gears are wheels with teeth that mesh together to transfer rotation. A) True B) False
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3
What is a lever? A) A bar that pivots on a fixed point to lift or move things B) A type of wheel C) A type of pulley D) A magnet
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4
True or false? Levers can make heavy loads easier to lift. A) True B) False
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5
What is the fulcrum of a lever? A) The pivot point that the lever turns around B) The heavy object being lifted C) The end you push down on D) The handle of the lever
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6
Label the three parts of this lever: effort, load and fulcrum.
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7
A see-saw is a kind of lever. Where is the fulcrum? A) The pivot in the middle that the plank rests on B) The child sitting on one end C) The handle bars on the side D) The ground beneath the see-saw
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8
True or false? A single fixed pulley changes the direction of a force, but you still need the same effort as the weight of the load. A) True B) False
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9
Two gears mesh together. The first gear is small, the second is large. What happens? A) The large gear turns more slowly than the small gear B) The large gear turns faster than the small gear C) Both gears turn at exactly the same speed D) The gears stop turning altogether
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10
Why is it easier to lift a heavy load using a lever? A) The lever lets you use a smaller effort over a longer distance B) The lever makes the load lighter C) The lever uses electricity to help you D) The lever stops the load from moving
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Answer key

Mechanisms: levers, pulleys and gears · for parents and teachers

1
wheel: wheel; rope: rope; load: load
A pulley has a grooved wheel with a rope running over it. The load hangs from one end and you pull the other end.
2
True
True. Gears are toothed wheels that lock into each other so that turning one wheel turns the other.
3
A bar that pivots on a fixed point to lift or move things
A lever is a simple machine: a bar that pivots around a fixed point (fulcrum) to lift loads with less effort.
4
True
True. Levers help us lift heavier loads with less effort by acting around a pivot.
5
The pivot point that the lever turns around
The fulcrum is the fixed pivot point. The lever turns around the fulcrum, with effort on one side and load on the other.
6
effort: effort; fulcrum: fulcrum; load: load
On a lever: you apply EFFORT at one end, the LOAD is at the other, and the FULCRUM is the pivot in between.
7
The pivot in the middle that the plank rests on
The fulcrum is the pivot at the centre of the see-saw. The plank rocks (rotates) around the fulcrum.
8
True
True. A fixed pulley lets you pull DOWN to lift something UP, but the effort needed is the same as the weight of the load.
9
The large gear turns more slowly than the small gear
A larger gear has more teeth, so each turn of the small gear only moves the big one a little. The big gear turns more slowly but with more force.
10
The lever lets you use a smaller effort over a longer distance
A lever swaps a small effort over a long distance for a big force over a short distance. The same total 'work' is done, but it feels easier.