# Fluid Mechanics Questions and Answers – Force Exerted by a Jet on a Stationary Curved Plate

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This set of Fluid Mechanics Multiple Choice Questions & Answers (MCQs) focuses on “Force Exerted by a Jet on a Stationary Curved Plate”.

1. Jet propulsion is a method of generating propulsive force by reaction of ________
a) Accelerating mass
b) Volume
c) Mass flow rate
d) Velocity

Explanation: Force exerted by a jet on a stationery plate happens in three cases. The three cases are classified depending on their position. Jet propulsion is a method of generating propulsive force by reaction of accelerating mass.

2. The propulsive force drives the jet in the ________
a) Backward direction
b) Forward direction
c) Perpendicular direction
d) Parallel movement

Explanation: Force exerted by a jet on a moving plate happens in three cases. The three cases are classified depending on their position. The propulsive force drives the jet in the forward direction. A good example is the aircraft or a boat.

3. In a stationery vertical plate, the jet after striking the plate will move _______
a) In opposite direction
b) Along the plate
c) Perpendicular to the plate
d) Parallel to the plate

Explanation: In a stationery vertical plate, the jet after striking the plate will move along the plate. It moves with respect to the angles that are developed with the plate.
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4. Jet propulsion works on the principle of________
a) Newton’s first law
b) Newton’s second law
c) Newton’s third law
d) Thermodynamic properties

Explanation: Jet propulsion works on the principle of Newton’s third law. Newton’s third law states that for every action, there is an equal and opposite reaction. Thus, the correct option is Newton’s third law.

5. What does Cv in jet propulsion equation stand for?
a) Area of orifice
b) Velocity
c) Temperature coefficient
d) Velocity coefficient

Explanation: In a jet propulsion, Cv stands for velocity coefficient. The main application in which this equation is applied is for a jet propulsion in the tank with orifice. Thus, the correct option is coefficient of velocity in the orifice.

6. Which among the following is the formula for Force when it strikes the plate?
a) pav2
b) pav
c) pa
d) maE

Explanation: The rate of change of momentum in the direction of force is given by the formula pav2. Where p= Density of the fluid flow, a = acceleration of the fluid particle and v = velocity of the fluid flowing.

7. The movement of ships and boats in water is due to __________
a) Water currents
b) Jet propulsion
c) Mass flow rate
d) Volumetric changes

Explanation: The movement of ships and boats in water is due to Jet propulsion. This mainly happens at the back of the ship or boat. It occurs as it exerts force on the ship and the boat. Thus, the correct option is Jet propulsion.

8. The inlet orifices are at what angle with the motion of the ship?
a) 0
b) 30
c) 60
d) 90

Explanation: The inlet orifices are at right angles with respect to the motion of the ship. The main purpose of the inlet orifice is to take water from the sea by the pump. Thus, the correct angle at which it moves is 90 degress.

9. Through inlet orifices, which are facing the direction of motion of the ship, the water from the sea can be taken by the pump.
a) True
b) False

Explanation: Through inlet orifices, which are facing the direction of motion of the ship, the water from the sea can be taken by the pump. We can also take the sea water from the pump when the inlet orifices are at right angles with respect to the motion of the ship.

10. Which among the following is a formula for force when it acts perpendicular to the direction of flow?
a) pav2 SinθCosθ
b) pav Sin2 θ
c) pa Sin2 θ
d) maE Sin2 θ

Explanation: When a force can be resolved into two components, one in the direction of the jet and the other perpendicular to the jet. The formula for force when it acts perpendicular to the direction of flow is equal to pav2SinθCosθ.

11. A jet strikes a curved plate at its ______
a) Sides
b) Surface
c) Centre
d) Does not strike

Explanation: A jet strikes a curved plate at its centre. Force exerted by a jet on a stationery plate happens in three cases. The three cases are classified depending on their position. The three cases are when plate is vertical, plate is inclined and plate is curved with respect to the jet.

12. Which among the following is the formula for relative velocity?
a) V + u
b) Vu
c) V – u
d) V/u

Explanation: Absolute relative velocity of a fluid related to the jet propulsion of the ship when the inlet orifices are at right angles to the direction of the motion of the ship is given by V+u.

13. What is the equation for efficiency of jet propulsion?
a) 2u/(V-2u)
b) 2u/(V+2u)
c) 2u/v
d) V/2u

Explanation: The efficiency of a jet propulsion of the ship when the inlet orifices are at right angles to the direction of the motion of the ship is given by 2u/(V+2u).

14. A jet after striking a smooth plate comes out with a __________ velocity.
a) Increased
b) Decreased
c) Same
d) Zero

Explanation: Force exerted by a jet on a stationery plate happens in three cases. The three cases are classified depending on their position. After it strikes a smooth plate, its velocity remains the same.

15. Component of velocity in direction of jet is -VCosθ. What does ‘θ’ indicate?
b) Angle made by jet and outlet tip
c) Angle made by jet and inlet tip
d) Tangent angle

Explanation: Component of velocity in direction of jet is -VCosθ. The negative sign indicates the that the taken velocity at the outlet is opposite to the jet of water coming out from the nozzle. ‘θ’ indicates the angle made by jet and inlet tip of the curved plate.

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