Question

Two cylindrical vessels fitted with pistons A and B of area of cross section 8 $c{m}^2$ and 320 $c{m}^2$ 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.

Answer 1

(i) Pressure on piston A = Weight on piston A / Area of piston A
$=\frac{4\times 10N}{8c{m}^2}=5N/c{m}^2$

(ii) As per Pascal's law, pressure on piston B = Pressure on piston A = $5N/c{m}^2$

(iii) Suing Pascal's law, $\frac{F_A}{A_A}=\frac{F_B}{A_B}\Rightarrow \frac{4\times 10}{8}=\frac{F_B}{320}\Rightarrow F_B=1600N$