4.5.3. Final Velocity and Force Calculation

Try these first

1. 1.

   What does the mass conservation equation state?

   Hint

   Think about the flow of fluids in and out of a system.

2. 2.

   What is incompressible flow?

   Hint

   Consider how gases behave under pressure.

3. 3.

   What does inflow equal in a closed fluid system?

   • Outflow
   • Weight
   • Density

   Hint

   Think about what happens to fluid in a container.

4. 4.

   Reynolds Transport Theorem helps calculate what?

   • True
   • False

   Hint

   Think about how momentum shares relate at system boundaries.

5. 5.

   A jet of water with an area of 3 cm² and velocity of 20 m/s strikes a plate moving at 15 m/s. Calculate the force acting on the plate.

   Hint

   Use mass flow rate concepts and consider the area.

6. 6.

   Evaluate the deceleration of a spacecraft that is 15,000 kg and has gases expelled at a rate of 90 kg/s at 2500 m/s to counteract a downward velocity of 600 m/s.

   Hint

   Consider the thrust force needed to balance the downward momentum effectively.