Question

The internal diameter of the tank is 1.22 m. The flow rate of water into the tank is 0.750 kg/s while the flow rate out of the tank is 1.25 kg/s.

a. What is the rate of change of the water level within the tank?

b. Is the water level rising, falling or remaining steady?

Answer 1

a) By mass balance

Min = 0.75 Kg/s

Mout = 1.25 Kg/s

b) now we will convert the derivative dM/dt to dH/dt

we know that

Mass = density * Volume = density * area* height

Mass = 1000* (Pi/4)*1.22²*H = 1168.98 H

now we will substitute M in dM/dt with above equation

As the rate of Change of Height w.r.t time is negative the level is slowly falling with time