Engineering Questions with Answers - Multiple Choice Questions

Machine Dynamics MCQ – Types of Dynamometers

1 - Question

The entire energy or power produced by the engine is absorbed by the friction resistances of the brake in which of the following dynamometers does?
a) Torsional brake dynamometer
b) Prony dynamometer
c) Belt Transmission dynamometer
d) Epicyclic train dynamometer

View Answer

Answer: b
Explanation: In absorption dynamometers the entire energy or power produced by the engine is absorbed by the friction resistances of the brake and is transformed into heat. Prony brake is an absorption dynamometer.




2 - Question

Belt transmission dynamometer is a transmission dynamometer.
a) True
b) False

View Answer

Answer: a
Explanation: Belt transmission dynamometer is a transmission dynamometer as a result the energy is not wasted in friction but is used for doing work.




3 - Question

Which of the following dynamometer belongs to a different type.
a) Prony brake dynamometer
b) Torsional dynamometer
c) Epicyclic train dynamometer
d) Belt transmission dynamometer

View Answer

Answer: a
Explanation: Prony brake dynamometer is an absorption dynamometer whereas the remaining three are transmission dynamometer.




4 - Question

Which of the following is not a characteristic of the rope brake dynamometer?
a) Energy loss in friction
b) Energy absorbed by frictional resistances
c) Energy utilization in work
d) Energy can be either utilized to do work or can be reused.

View Answer

Answer: b
Explanation: Rope brake dynamometer is an absorption dynamometer hence all the energy is absorbed by frictional resistances and gets converted into heat.




5 - Question

Which of the following is not a characteristic of the Torsional dynamometer.
a) Conversion of energy into heat
b) Conversion of energy into work
c) Utilization of engine power
d) Energy can be either utilized to do work or can be reused.

View Answer

Answer: a
Explanation: Torsional dynamometer is a transmission dynamometer as a result the energy is not wasted in friction but is used for doing work. In case of absorption dynamometers, the energy is wasted into heat.




6 - Question

Flywheel diameter 1.2 m; diameter of the rope 12.5 mm; engine speed 100 r.p.m.; dead load on the brake 600 N; spring balance reading 150 N. Using this data, calculate the brake power of the engine in kW.
a) 2.85
b) 5.71
c) 11.4
d) 4.88

View Answer

Answer: a
Explanation: The brake power of an engine is given by the relation:
B.P = [(W-S)π (D+d)N]/60
= (600 – 150)π (1.2+0.0125)100]/60 W
B.P = 2.85 kW.




7 - Question

On which of the following factor, the power of a torsion dynamometer does not depend?
a) Speed
b) Torque
c) Angle of twist
d) Friction

View Answer

Answer: d
Explanation: Power is directly proportional to Torque and Speed,
Torque is directly proportional to the angle of twist. Thus power also depends on the angle of twist.




8 - Question

Transmission dynamometer uses the energy is used to do work.
a) True
b) False

View Answer

Answer: a
Explanation: Absorption dynamometers lose their energy through friction but transmission dynamometer utilizes the same energy for doing work.

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