Fluid Mechanics

Question 1

What is the definition of a fluid?

Answer 1

A fluid is any substance that is able to flow if it is not confined or restricted.

Question 2

What are the two main classifications of fluids?

Answer 2

Liquids and gases.

Question 3

What is a significant difference between liquids and gases when a force is applied?

Answer 3

Liquids tend to be incompressible; gases are highly compressible.

Question 4

What principle explains the theory of lift on a wing and the force generated by a hydraulic system?

Answer 4

The laws of fluid mechanics.

Question 5

What is buoyant force?

Answer 5

The upward force that any fluid exerts on a body submerged in it.

Question 6

When will an object float in a fluid?

Answer 6

If the buoyant force is greater than the weight of the object.

Question 7

What happens to objects denser than the fluid when submerged?

Answer 7

They sink but appear to lose a part of their weight.

Question 8

What is Archimedes’ principle?

Answer 8

The buoyant force exerted on a submerged body is equal to the weight of the fluid the body displaces.

Question 9

How can buoyant force be calculated?

Answer 9

Buoyant Force = Volume of Object × Density of Fluid Displaced.

Question 10

If the buoyant force is less than the object’s weight, what will happen?

Answer 10

The object will sink.

Question 11

What is the formula for calculating buoyant force?

Answer 11

Buoyant Force = Volume of Object × Density of Fluid Displaced.

Question 12

What is static pressure?

Answer 12

Pressure based on the column height of a fluid.

Question 13

What is ram pressure?

Answer 13

Pressure when the velocity of a fluid is converted to pressure.

Question 14

What does Pascal’s Law state?

Answer 14

Pressure set up in a fluid acts equally in all directions.

Question 15

What is the formula for force in relation to pressure and area?

Answer 15

Force = Pressure × Area.

Question 16

What is mechanical advantage in a hydraulic system?

Answer 16

The relationship between the output force and the input force.

Question 17

What happens to work in a hydraulic system?

Answer 17

No machine allows us to gain work; we get no more work out than we put in.

Question 18

What does Bernoulli’s principle explain?

Answer 18

The static pressure of a fluid decreases at points where the velocity of the fluid increases.

Question 19

What is a venturi tube?

Answer 19

A tube with varying cross-sectional areas used to illustrate Bernoulli’s principle.

Question 20

What occurs in the narrow section of a venturi tube?

Answer 20

The fluid moves at a higher velocity, producing a lower pressure.

Question 21

Fill in the blank: Buoyant Force = Volume of Object × __________.

Answer 21

Density of Fluid Displaced.

Question 22

True or False: An airship is classified as a heavier-than-air aircraft.

Answer 22

False.

Question 23

What is the relationship between the input piston area and output piston area in a hydraulic system?

Answer 23

Input Piston Area (Distance Moved) = Output Piston Area (Distance Moved).

Question 24

What is the pressure at the bottom of a container filled with liquid dependent on?

Answer 24

The height of the liquid.

Question 25

If a fluid is at rest, how is the pressure distributed within the fluid?

Answer 25

It is equal at any given level.

Question 26

How much larger must the floats be for a seaplane according to regulations?

Answer 26

80 percent larger than the minimum needed to support the airplane.

Question 27

What does the venturi principle explain about fluid flow in a tube?

Answer 27

As the tube narrows, the fluid must maintain the same volume, resulting in higher velocity and lower pressure in the narrow section. ## Footnote This principle is often illustrated by the behavior of fluids in pipes with varying diameters.

Question 28

In a float-type carburetor, what happens to the static pressure as air flows through the venturi?

Answer 28

The static pressure is reduced as the air flows through the venturi. ## Footnote This reduction in pressure allows fuel, which is under higher pressure, to flow into the lower pressure area and mix with air.

Question 29

How does Bernoulli's principle relate to the generation of lift on an airplane wing?

Answer 29

The airspeed over the curved top surface of the wing increases, causing static pressure to decrease, creating a pressure difference that generates lift. ## Footnote The flat bottom surface of the wing maintains higher static pressure compared to the top.

Question 30

True or False: The inlet duct of a turbine engine on a subsonic airplane has a converging shape.

Answer 30

False ## Footnote The inlet duct is diverging in shape, which is essential for aerodynamics at subsonic speeds.

Question 31

Fill in the blank: The principle that describes the relationship between fluid velocity and pressure is known as _______.

Answer 31

Bernoulli’s principle ## Footnote Bernoulli's principle is fundamental in fluid dynamics and has applications in various engineering fields.

Question 32

What occurs to the pressure of air as it flows over the top of a wing?

Answer 32

The static pressure decreases. ## Footnote This decrease in pressure is essential for generating lift, as it contrasts with the higher pressure on the bottom of the wing.

Question 33

What is the result of the pressure difference created by the airflow over an airplane wing?

Answer 33

It creates lift on the wing. ## Footnote This lift is crucial for the flight of the airplane, allowing it to rise and maintain altitude.