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