Engineering Questions with Answers - Multiple Choice Questions
Machine Dynamics MCQ – Controlling Force
1 - Question
The controlling force acting on the governor is also known as ________
a) Centripetal force
b) Centrifugal force
c) Governor effort
d) Piston effort
View Answer
Answer: a
Explanation: When a governor rotates at a steady speed, an inward force acts on the body which is centripetal in nature. This force is called a controlling force.
2 - Question
Controlling force is in the same direction as centrifugal force.
a) True
b) False
View Answer
Answer: b
Explanation: When a governor rotates at a steady speed, an inward force acts on the body which is centripetal in nature. This force is called controlling force and acts in the opposite direction to that of centrifugal force.
3 - Question
If F=m.ω2.r represents the centrifugal force then which of the following expressions represents controlling force.
a) F
b) 2F
c) -2F
d) -F
View Answer
Answer: d
Explanation: Inward force acts on the body of the governor which is centripetal in nature. This force is called controlling force and acts in the opposite direction to that of centrifugal force.
4 - Question
Controlling force in the porter governors is due to which of the following components?
a) Spring
b) Weight of sleeve
c) Weight of governor
d) Piston effort
View Answer
Answer: b
Explanation: The controlling force is provided by the weight of the sleeve and balls as in Porter governor and by the spring and weight as in Hartnell governor.
5 - Question
Controlling force in the Hartnell governors is due to which of the following components?
a) Weight of balls
b) Weight of sleeve
c) Spring
d) Piston effort
View Answer
Answer: b
Explanation: The controlling force is provided by the weight of the sleeve and balls in case of Porter governor and by the spring and weight in case of Hartnell governor.
6 - Question
If the mass of the ball is 7.5 kg and the controlling force is 200N with an angular velocity of 100 rpm, find the radius.
a) 24 cm
b) 28 cm
c) 30 cm
d) 20 cm
View Answer
Answer: a
Explanation: F=m.ω2.r
200 = 7.5 (2πx100/60)2.r
Therefore r = 0.243m.
7 - Question
If the mass of the ball is 25 kg and the controlling force is 450 N with an angular velocity of 150 rpm, find the radius.
a) 7.2 cm
b) 7.9 cm
c) 8.3 cm
d) 12.3 cm
View Answer
Answer: b
Explanation: F = m.ω2.r
450 = 25 (2πx150/60)2.r
18 = 246.7.r
Therefore r = 0.072m.
8 - Question
Control force diagram enables to examine stability and sensitivity of the governor.
a) True
b) False
View Answer
Answer: a
Explanation: When the graph is drawn between the controlling force (Fc) as y-axis and radius of rotation of the balls (r) as x-axis, then the graph obtained is known as controlling force diagram of the governor. This diagram enables the stability and sensitiveness of the governor to be examined and also shows clearly the effect of friction.
9 - Question
Which of the following quantities cannot be examined from controlling force diagram?
a) Sensitivity
b) Stability
c) Effect of friction
d) Power of governor
View Answer
Answer: d
Explanation: The graph between the controlling force (Fc) as y-axis and radius of rotation of the balls (r) as x-axis is known as controlling force diagram. This diagram enables us to examine the stability and sensitiveness of the governor along with the effect of friction.