Question

Q . Two cylindrical vessels fitted with pistons A and B of area of cross section 8 cm² and 320 crn² respectively, are joined at their bottom by a tube and they are completely filled with water. When a mass of 4 kg is placed on piston A, find : (i) the pressure on piston A, (ii) the pressure on piston B, and (iii) the thrust on piston B.
Ans. (i) 0.5 kgf cm^-2, (ii) 0.5 kgf crn^-2 (iii) 160 kgf


Q. What force is applied on a piston of area of cross section 2 cm² to obtain a force 150 N on the piston of area of cross section 12 cm² in a hydraulic machine ?
Ans. 25N

Answer 1

dear student
i) pressure exerted by 4kg block on piston a is F/A that is 4 kgf/ 8 cm² =0.5kgfcm^-2

ii) by pascle law pressure change is distributed equally in the all parts of fluid so the same pressure 0.5kgfcm^-2 will be exerted on piston B
iii) Thrust = pressure * area = 0.5kgfcm^-2*320 cm² = 160 kgf
​
$$\begin{gathered} asbypascellawsamechangeinpressureisdistributedeverywher \\ so\frac{F1}{A1}=\frac{F2}{A2} \\ \frac{F1}{2c{m}^2}=\frac{150}{12c{m}^2}whichgivesF1=25N \end{gathered}$$