Question

Solve:

(1) Ajit carries a load of 17 kg from the ground on his head and takes it to the height of 2 m from the ground. Calculate the work done by him. (333.2 J)

(2) The velocity of a car increases from 54 km/hr to 72 km/hr. If the mass of the car is 1500 kg find the work done to increase the velocity. (131250 J)

Answer 1

(1) Mass of a load, m = 17 kg

Displacement of the block, h = 2 m

Acceleration due to gravity, g = 9.8 m/s²

Force applied by Ajit, F = Weight of the load

⇒ F = mg = 166.6 N

Work done by Ajit, W = Fh

⇒ W = 166.6₂

⇒ W = 333.2 J

(2) Initial velocity of car, u = 54 km/h = 54

_{Final velocity of car, v = 72 km/h = 72}

_{Mass of the car = 1500 kg}

_{Work done to increase the velocity, W =…….?}

_{Change in kinetic energy of a car be}

_{Change in kinetic energy = Work done}

_{So, work done to increase the velocity, W = 131250 J.}