This is called a turning effect. Whenever you swing open a door, you are exploiting a turning effect - the hinge is the fulcrum. The size of a turning force is called a moment. Levers are devices that multiply your efforts by using moments. The further away from the fulcrum the effort is applied compared to the load,the less force needed to move the load.
Some levers have the fulcrum between the effort and the load, as in crowbars and scissors.
Other levers have the load between the effort and the fulcrum ,as in wheelbarrows, screwdrivers and nutcrackers. Another sort of lever has the effort between the load and the fulcrum as in tweezers. Gears Gears make it easier to cycle uphill, or for a car to accelerate from a standstill, by spreading the effort over a greater distance. They are basically pairs of wheels of different sizes that turn together, making one shaft turn another. The number of times the driving wheel turns for each turn of the wheel being driven by the engine is called the gear ratio.