Simple Machines

Simple Machines

A lever is a simple machine. It consists of a rigid bar, which is capable of turning around a pivot, which is also called a fulcrum. Generally, we use a rod, which can rotate freely about the fulcrum.

For lever, we generally use two more terms apart from the general terms used for all the machines.

• Load Arm— It is the distance between the fulcrum and the point where the load is applied.

• Effort Arm — It is the distance between the fulcrum and the point where the effort is put.

The working of all levers is based on a common principle, which is called principle of lever.

Principle of lever

Load × Load arm = Effort × Effort arm

If we rearrange the equation, we obtain

Therefore, the mechanical advantage of a lever is nothing but the ratio of the length of its effort arm to the load arm.

Different Types of Lever

Levers are classified into three types depending upon the positions of load, fulcrum, and effort.

Lever of first order

When the fulcrum is situated between load and effort, we call it a lever of first order. For example, beam balance, a crowbar, a seesaw.

Crowbar	Beam Balance	Seesaw

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