Question

What is a lever? What is the principle of its working?

Answer 1

Levers:

1. It is the simplest and most common machine used in everyday life.
2. A lever is a rigid, straight or bent bar capable of rotating around a fixed point or its axis called the fulcrum.
3. A fulcrum (F) does not move but remains fixed when a lever is in use.

Principle of a lever:

1. According to the principle of moments, in the equilibrium position of the lever,

$$\begin{gathered} Momentofloadaboutthefulcrum=Momentofeffortaboutthefulcrum \\ Load\times Loadarm=Effort\times Effortarm \\ \frac{Load}{Effort}=\frac{Effortarm}{Loadarm} \\ MA=\frac{Effortarm}{Loadarm} \end{gathered}$$

This expression is known as the law of levers.