Question

If an object of mass $50kg$ is lifted to a height of $3m$ then find its potential energy. If this object falls freely from that height then find its kinetic energy when it is half way distance. ($g=10m/s^2$)

Answer 1

Given:-

Mass = $50Kg$

Height to which mass is lifted = $3m$

Potential energy = $mgh=50\times 10\times 3=1500Joule$

Now, from Energy conservation law

$△P.E=△K.E$

$\Rightarrow$ $mg{h}^{\prime }=\frac{1}{2}m{V}^2$

$\Rightarrow$ $V=\sqrt{2g{h}^{\prime }}=\sqrt{2\times 10\times 25}=\sqrt{500}=10\sqrt{5}m/s$