Question

34 In Example 13-3, a force of 147 N is applied to a small piston to lift a car that weighs 14,700 N. Demonstrate that this does not violate the law of conservation of mechani cal energy by showing that, when the car is lifted some dis- tance h, the work done by the 147-N force acting on the small piston equals the work done by the large piston on the car.

Answer 1

let area of piston be 'a' and that of platform on which car is there be 'A'

the pressure will be same in the fluid at the platform and also at piston

volume of fluid displaced by piston will be equal to volume of water displaced underneath platform

Work done is given by pressure*change in volume

Therefore, work done is equal under platform and piston

Hence, energy is conserved