Question

Question 17
Calculate the work required to be done to stop a car of $1500kg$ moving at a velocity of $60kmph$?

Answer 1

Kinetic energy, $E_k=\frac{1}{2}m{v}^2$
where, mass of car, $m=1500kg$
velocity of car, $v=60kmph=\frac{60\times 5}{18}m{s}^{-1}$
$\therefore E_k=\frac{1}{2}\times 1500\times (60\times \frac{5}{18}{)}^2=20.8\times {10}^{4}J$
Hence, $20.8\times {10}^{4}J$ of work is required to stop the car.