Mechanical Properties of Fluids · Question 29

In a hydraulic lift, the surface area of the input piston is 6 cm2 and that of the output piston is 1500 cm2. If 100 N force is applied to the input piston to raise the output piston by 20 cm, then the work done is kJ.

Answer

5

Solution

Pascal's law: F1A1 = F2A2

F2 = 100 15006 = 25000 N

Work done in raising the output piston by 0.20 m:

W = F2 0.20 = 25000 0.20 = 5000 J

W = 5 kJ (the same work is done by the input force, since V = A1x1 = A2x2)

Answer: 5