Engineering Questions with Answers - Multiple Choice Questions

Home » MCQs » Aeronautical Engineering » Machine Dynamics MCQ – Controlling Force Diagram for a Spring-controlled Governor

# Machine Dynamics MCQ – Controlling Force Diagram for a Spring-controlled Governor

Let r represent the radius of rotation, then for stability of a spring controlled governor, which of the following relation regarding controlling force is true? (a, b are constants)

a) Fc = ar-b

b) Fc = ar +b

c) Fc = ar

d) Fc = a

**
View Answer**

Answer: a

Explanation: The relation between the controlling force (FC) and the radius of rotation (r) for the stability of spring controlled governors is given by the following equation:

Fc = ar-b.

If the line intersects the Controlling force axis in positive direction in the controlling force diagram of the spring controlled governor, then it is stable.

a) True

b) False

**
View Answer**

Answer: b

Explanation: If the line intersects the Controlling force axis in negative direction in the controlling force diagram of the spring controlled governor, then it is stable.

Fc = ar-b

Let r represent the radius of rotation, then for an unstable spring controlled governor, which of the following relation regarding controlling force is true? (a,b are constants)

a) Fc = ar-b

b) Fc = ar +b

c) Fc = ar

d) Fc = a

**
View Answer**

Answer: b

Explanation: The relation between the controlling force (FC) and the radius of rotation (r) for the unstability of spring controlled governors is given by the following equation:

Fc = ar+b.

Let r represent the radius of rotation, then for an isochronous spring controlled governor, which of the following relation regarding controlling force is true? (a,b are constants)

a) Fc = ar-b

b) Fc = ar +b

c) Fc = ar

d) Fc = a

**
View Answer**

Answer: c

Explanation: The relation between the controlling force (FC) and the radius of rotation (r) for the instability of spring controlled governors is given by the following equation:

Fc = ar.

In the given figure x axis is the radius of rotation and y axis is the controlling force, identify the correct option.

a) Curve represents isochronous governor

b) Curve represents stable governor

c) Curve represents unstable governor

d) Curve represents sensetive governor

**
View Answer**

Answer: a

Explanation: In the given figure, the straight line is passing through the origin thus following a relation

Fc = ar. Since there are no constants it represents an isochronous governor.

In the given figure x axis is the radius of rotation and y axis is the controlling force, identify the correct option. (For a spring controlled governor)

a) Curve represents isochronous governor

b) Curve represents stable governor

c) Curve represents unstable governor

d) Curve represents sensetive governor

**
View Answer**

Answer: b

Explanation: In the given figure, the straight line is below the axis representing the controlling force thus following a relation

Fc = ar – b. Since there is a negative constant it represents a stable governor.

In the given figure x axis is the radius of rotation and y axis is the controlling force, identify the correct option. (For a spring controlled governor)

a) Curve represents isochronous governor

b) Curve represents stable governor

c) Curve represents unstable governor

d) Curve represents sensetive governor

**
View Answer**

Answer: c

Explanation: In the given figure, the straight line is above the axis representing the controlling force thus following a relation

Fc = ar + b. Since there is a negative constant it represents an unstable governor

It is possible that the equilibrium speed of the governor decreases with an increase of the radius of rotation of balls.

a) True

b) False

**
View Answer**

Answer: b

Explanation: If the equilibrium speed of the governor decreases with an increase of the radius of rotation of balls then Fc/r decreases as r increases. This is impracticable.