Levers and gears: Forces: Physics: GCSE (9:1)

Force multiplier

Something that is used to increase the effect of a force and is used to move large or heavy objects e.g. levers and gears

Lever

A simple machine consisting of a pivot, an effort and a load

Pivot

The point around which something can rotate or turn

Effort

The force used to move a load over a distance

Load

The overall force that is exerted by an object on a surface

First-class lever

When the pivot is in the middle with the effort and load on either side e.g. a see-saw

Second-class lever

When the load is in the middle with the pivot and effort on either side e.g. a wheelbarrow

Third-class lever

When the effort is in the middle with the pivot and load on either side e.g. tweezers, cooking tongs

Gears

Wheels with toothed edges that rotate about an axle or shaft

Teeth (of a gear)

The teeth of one gear fit into the teeth of another gear meaning one gear turns the other

Direction of rotation of gears

Where the gears meet, the teeth must both move in the same direction which means that the gears rotate in opposite directions

What happens when a large gear is driven by a smaller one

The large gear will rotate slowly but will have a greater moment than the smaller gear

What happens when a small gear is driven by a larger one

The small gear will rotate quickly but will have a smaller moment than the larger gear