4.2.2. Force Calculation in Moving Conditions

Try these first

1. 1.

   What does mass conservation state?

   Hint

   Think of inflow versus outflow.

2. 2.

   Define incompressible flow.

   Hint

   Consider fluids like water under standard conditions.

3. 3.

   What principle states that mass entering a control volume equals mass leaving it?

   • A. Mass Conservation
   • B. Energy Conservation
   • C. Momentum Conservation

   Hint

   Think about the flow of mass through any system.

4. 4.

   Is the flow of a fluid behave differently depending on whether it is compressible or incompressible?

   • True
   • False

   Hint

   Consider how density variations influence flow behavior.

5. 5.

   A jet of water strikes a stationary plate at a velocity of 10 m/s with a cross-sectional area of 0.01 m² and density of 1000 kg/m³. Calculate the force acting on the plate due to the jet.

   Hint

   Focus on applying the momentum change to find the force.

6. 6.

   During re-entry, a spacecraft expires propellants at a rate of 1 kg/s with an exit velocity of 2500 m/s. If the spacecraft's mass is 10000 kg and it was descending at 300 m/s, find the thrust and deceleration.

   Hint

   Remember, thrust affects momentum and deceleration.