The work required to be done to stop an object of 300 kg moving at a velocity of 36 km/h

Answer:

Mass of the car (m) = 1500 kg

Velocity (v) = 60 km/hr

v = 60 x 5/18

v = 16.67 m/s

The car is in motion, so its energy is,

Kinetic Energy (K.E) = 1 /2 mv2

\(\begin{array}{l}K.E = \frac{1}{2}\times 1500 \times ( 16.67)^{2}\end{array} \)

K.E = 1/ 2 × (1500) × 277.88 J

K.E = 208416.7 J

The kinetic energy of the car, when it comes to rest = 0 J

Work done on object = change in kinetic energy

= 208416.7 – 0

= 208416.7 J

Hence, the work required to stop the car is 208416.7 J.