A machine is a device that helps us to overcome a load with less effort or force. Devices that are classed as simple machines are: The lever The pulley The wedge The screw The inclined and plane The wheel and axel
A lever is an example of a simple machine which turns about a fixed point called the fulcrum (F) when a force, called the effort (E), is applied to overcome a resisting force called the load (L). Using a lever to overcome a large load with a small effort.
Thevarious devices that use the principle of levers
Load (L): the boulder to be lift Effort (E): the force used by the man to lift the boulder Fulcrum (F): the point about which the stick turns
Fulcrum is between the effort and the load Effort moves a longer distance but the load moves a shorter distance Fulcrum near to the load
Load is between the fulcrum and the effort Effort moves a longer distance but the load moves a shorter distance
Effort is between the fulcrum and the load Effort moves a shorter distance but the load moves a longer distance
When a force is applied to an object, it can turn the object about a certain point called the fulcrum or pivot. This turning effect of a force is called the moment of a force. Moment of a force depends on: The force (F) applied The perpendicular distance (d) from the pivot to the force (F).
The great pyramids of Egypt and the Great Wall ofChina were built using simple tools such as levers,rollers, wedges and inclined planes.
Today we have invented, designed and built complex machines Trains travelling at high speeds on land Ships and submarines travelling on the sea and under the sea. Supersonic planes flying through the air Spaces exploring outer space and landing astronauts on the moon.