Certain force acting on a 20 kg mass changes its velocity from 5 m/s to 2 m/s. Calculate work done by the force

Initial velocity (u) = 5 m/s

Final velocity (v) = 2 m/s

Work done (W)  $=Force\left(F\right)\times displacement\left(S\right)$

We know = $v^2-u^2=2as$

$s=\frac{v^2-u^2}{2a}$

$=ma\times \frac{v^2-u^2}{2a}$

$=20\times \frac{{\left(2\right)}^2-{\left(5\right)}^2}{2}=20\times \frac{4-25}{2}=20\times -10.5g$

$=20\times \frac{-105}{10}=-210J$