3.1.7. Conservation of Mass

Try these first

1. 1.

   What is a control volume?

   Hint

   Think about how we simplify complex systems.

2. 2.

   Define mass conservation.

   Hint

   It relates to what happens in a closed system.

3. 3.

   What is the primary principle of mass conservation in fluid mechanics?

   • Mass can be created
   • Mass remains constant
   • Mass can be destroyed

   Hint

   Think about what happens in a closed system.

4. 4.

   True or False: The integral approach in fluid mechanics ignores the interior conditions of control volumes.

   • True
   • False

   Hint

   Consider what we know and don’t know about the 'black box'.

5. 5.

   A control volume is established around a pipe segment with water flowing in and out. Calculate the mass flow rates if the inlet has a velocity of 3 m/s and an area of 2 m² with water density 1000 kg/m³.

   Hint

   Use the mass flow rate formula: mass flow rate = density × area × velocity.

6. 6.

   Visualize a situation with a fixed control volume and mass entering it at a different speed than mass exiting. How does this affect total mass over time?

   Hint

   Think about the relationship between the incoming and outgoing mass flux.