Question

Two cylindrical vessels fitted with pistons ‘A’ and ‘B’ having area of cross section

8 cm2

and 320 cm2

respectively, are joined at their bottom by a tube and they are

completely filled with water. When a mass of 4kg is placed on piston ‘A’, calculate:

i) Thrust on piston A ii) Pressure on piston A

iii) Pressure on piston B iv) Thrust on piston B​

Answer 1

Let E be the effort applied on the smaller piston A and L be the load required on the larger piston B.
Area of cross section of pistion A=8cm
2

Area of cross section of pistion A=320cm
2

(i) Pressure acting on piston A in the downward direction =Thrust/Area=E/8=4/8=0.5
∴Pressure acting on water =E/8=0.5 (according to Pascal's Law)
(ii) ∴ Pressure acting on piston B=E/8=0.5 (according to Pascal's Law)
(iii) Thrust acting on piston B in the upward direction =Pressure ×Area ofB

=
8
E×320
​
=