Chapter 4, Problem 4.28P

(a)

Interpretation Introduction

Interpretation:

The time for the water level to drop to 2 ft from the bottom of the tank is to be calculated.

Concept Introduction:

In a system, a conserved quantity (total mass, mass of a particular species, energy or momentum) is balanced and can be written as:

  $input+generation-output-consumpumtion=accumulation$

Here, ‘input’ is the stream which enters the system. ‘generation’ is the term used for the quantity that is produced within the system. ‘output’ is the stream which leaves the system. ‘consumption’ is the term used for the quantity that is consumed within the system. ‘accumulation’ is used for the quantity which is builds up within the system.

All the equations which are formed are then solved simultaneously to calculate the values of the unknown variables.

The formula to calculate mass flow rate $\left(\dot{m}\right)$ of a fluid from its density $\left(\rho \right)$ and volumetric flow rate $\left(\dot{V}\right)$ is:

  $\dot{m}=\rho \dot{V}$......... (1)

(b)

Interpretation Introduction

Interpretation:

The time for the tank to drain completely is to be calculated.

Concept Introduction:

In a system, a conserved quantity (total mass, mass of a particular species, energy or momentum) is balanced and can be written as:

  $input+generation-output-consumpumtion=accumulation$

Here, ‘input’ is the stream which enters the system. ‘generation’ is the term used for the quantity that is produced within the system. ‘output’ is the stream which leaves the system. ‘consumption’ is the term used for the quantity that is consumed within the system. ‘accumulation’ is used for the quantity which is builds up within the system.

All the equations which are formed are then solved simultaneously to calculate the values of the unknown variables.

The formula to calculate mass flow rate $\left(\dot{m}\right)$ of a fluid from its density $\left(\rho \right)$ and volumetric flow rate $\left(\dot{V}\right)$ is:

  $\dot{m}=\rho \dot{V}$......... (1)