18.7.3. Gravity Force Calculation

Try these first

1. 1.

   What is the definition of body forces?

   Hint

   Think of forces that act from within.

2. 2.

   Give an example of a surface force in fluid mechanics.

   Hint

   Consider the forces acting at the boundary of fluid.

3. 3.

   What describes a body force?

   • Acting at the surface only
   • Force acting throughout the fluid volume
   • A frictional force on a surface

   Hint

   Consider how gravity acts on the entire mass.

4. 4.

   True or False: Surface forces include friction and pressure.

   • True
   • False

   Hint

   Think about forces acting at the boundaries.

5. 5.

   A cylindrical tank full of water is subjected to an external gravitational force. Derive the expression for the total vertical gravitational force acting on the bottom of the tank.

   Hint

   Think about calculating volume first using the formula.

6. 6.

   In a fluid system, analyze how both body and surface forces would alter the flow if gravity were absent. What implications does this have?

   Hint

   Consider how pressure drives the flow in various systems.