Question

An open rectangular tank 4m long and 2.5m wide contains an oil of specific gravity 0.85 up to a depth of 1.5m. Determine the total pressure on the bottom of the tank, when the tank is moving with an acceleration of $g/2m/s^2$ vertically upwards

• A. $187.65kPa$
• B. $62.55kPa$
• C. $100kPa$
• D. $78kPa$

Answer 1

The correct option is A $187.65kPa$

Tank is moving upwards with an acceleration of $\frac{g}{2}m/s^2$

Thus for the system $g_{eff}$ = $\frac{3g}{2}m/s^2$

Pressure increases with depth according to the formula : $P=$ $P_0+\rho g_{eff}h$

Also pressure due to the weight of the liquid = $\rho Vg/A$ = $\rho Vh=22.5㎩$

Here $P_0$ = 0. Because atmospheric pressure is applied from both sides thus it;s cancelled.

$\therefore$ Pressure = $\rho g_{eff}h=18742.5㎩$ $+22.5㎩$ $=187.65kPa$