Define kinetic energy. Give its unit and dimensional formula and mention works by using it.
Define kinetic energy. Give its unit and dimensional formula and mention works by using it.
The energy of a body is the ability (or capacity) of the body to do work.
Half of the product of the mass of a body and the square of its velocity is defined as kinetic energy $(K)$ of the body.
$\therefore \quad \mathrm{K}=\frac{1}{2} m v^{2}$ where $m=$ mass of body
$\nu=$ velocity or speed of the body.
Unit of kinetic energy is same as the unit of work. So, its $SI$ unit is Joule $(J)$ and $CGS$ unit is erg. Dimensional formula of kinetic energy is $\left[\mathrm{M}^{1} \mathrm{~L}^{2} \mathrm{~T}^{-2}\right]$.
Hence, a body of definite mass moving with more speed would have more kinetic energy compared to the kinetic energy of the same body moving with comparatively lesser speed.
Kinetic energy is a scalar quantity. The kinetic energy of a body indicate the magnitude of work by the body during its motion.
The kinetic energy of a fast flowing stream has been used to grind grains.
Sailing ships employ the kinetic energy of the wind and electricity is generated by wind mill.
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$(i)$ directly proportional to $\sqrt t$
$(ii)$ inversely proportional to $\sqrt t$
$(iii)$ directly proportional to the speed of the body
$(iv)$ inversely proportional to the speed of body
If the kinetic energy of a body is directly proportional to time $t,$ the magnitude of force acting on the body is
$(i)$ directly proportional to $\sqrt t$
$(ii)$ inversely proportional to $\sqrt t$
$(iii)$ directly proportional to the speed of the body
$(iv)$ inversely proportional to the speed of body