Calculate the work required to be done to stop a car of 1500kg moving at a velocity of 60km/h?​

Solution:

Mass of the car = 1500 kg

Velocity = 60 km/hr = 60 x 5/18 = 16.67 m/s

The car is in motion, so its energy = kinetic energy = 1 /2 mv2

= 1 /2 (1500) ( 50/ 3 ) 2 J

= 1/ 2 × (1500) × 2500/ 9 J

= 20.8 x 104J

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

Work done on object = change in kinetic energy

= 20.8 x 104J − 0 J

= 20.8 x 104J