Question

A car is moving with uniform velocity of $15{ms}^{-1}$. What is the kinetic energy of a boy of mass $40kg$ sitting in the car?

Answer 1

Velocity of the boy $=$ velocity of the car
Kinetic energy possessed by the boy $=\frac{1}{2}m{v}^2$ Here $m=40kg$, $v=15m{s}^{-1}$
$=\frac{1}{2}\times 40kg\times {\left(15m{s}^{-1}\right)}^2$
$=4500J$