# What is work in physics?

### What is work?

Scalar product of force and displacement is called work.

$$W = \vec{F}.\vec{S}\cos \theta$$

Work is a scalar quantity. The dimensional formula of work is [ M1L2T-2 ]. SI unit of work is joule. CGS unit of work is erg.

Relation between joule and erg is
1 joule = 107 erg.

In terms of rectangular components, work is
W = x Fx + y Fy + z Fz

### Types of work

#### Positive work

If angle between $$\vec{F}$$ and $$\vec{S}$$ lies between 00 and 900, then work done is positive.

#### Negative work

If angle between $$\vec{F}$$ and $$\vec{S}$$ lies between 900 and 1800, then work done is negetive.

#### Negative work

The work done is zero, if

• there is no displacement
• no force is acting on the body
• angle between $$\vec{F}$$ and $$\vec{S}$$ is 900