# Machine Dynamics Questions and Answers – Epicyclic-train Dynamometers

This set of Machine Dynamics Multiple Choice Questions & Answers (MCQs) focuses on “Epicyclic-train Dynamometers”.

1. Which of the following gears is not a part of an epicyclic train dynamometer?
a) Spur gear
b) Pinion gear
c) Annular gear
d) Helical gear

Explanation: An epicyclic train dynamometer consists of simple epicyclic gear trains including spur gear, annular gear with internal toothing and pinion gear.

2. An epicyclic-train dynamometer consists of a simple epicyclic train of gears.
a) True
b) False

Explanation: An epicyclic train dynamometer consists of simple epicyclic gear trains including pinion gear, annular gear with internal teeth and spur gear.

3. Which of the following statement is true regarding epicyclic train dynamometer.
a) Spur gear rotates in clockwise direction
b) Annular gear rotates in clockwise direction
c) Spur gear rotates is meshes with both annular and pinion
d) Annular gear rotates in anticlockwise direction

Explanation: The spur gear is keyed to the driving shaft and rotates in anticlockwise direction. The annular gear rotates in clockwise direction and is keyed to the engine shaft.

4. Which of the following dynamometers have a pinion meshing with two gears?
a) Prony brake dynamometer
b) Epicyclic train dynamometer
c) Torsional dynamometer
d) Belt transmission dynamometer

Explanation: In an epicyclic train dynamometer, three gears are used namely Spur gear annular gear and pinion gear. The pinion gear is in mesh with annular and spur gear.

5. Which of the following dynamometer type differs from an Epicyclic train dynamometer?
a) Belt transmission
b) Torsional dynamometer
c) Transmission dynamometer
d) Prony brake dynamometer

Explanation: Prony brake dynamometer is an absorption dynamometer and uses all the energy obtained by the engine to convert it into heat, whereas the remaining three are transmission dynamometers.
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6. If the friction of the pin on which the pinion rotates is neglected, which of the following force is equal to the tangential effort exerted by the spur gear on the pinion
a) Radial effort exerted by the spur gear on the pinion
b) Tangential reaction of the annular gear on the pinion
c) Radial reaction of the annular gear on the pinion
d) Piston effort

Explanation: If the friction of the pin on which the pinion rotates is neglected, then the tangential effort P exerted by the spur gear on the pinion and the tangential reaction of the annular gear on the pinion are equal.

7. The upward force is balanced by ________
a) Radial effort exerted by the spur gear on the pinion
b) Tangential reaction of the annular gear on the pinion
c) Radial reaction of the annular gear on the pinion

Explanation: The reaction force by the gears acts in the upward direction tends to rotate the lever about its fulcrum. These upward forces are balanced by the dead weight at the end of the lever.

8. The dead weight at the end of the fulcrum causes rotation of lever about fulcrum.
a) True
b) False

Explanation: The reaction effort by the gears acts in the upward direction which has a tendency to rotate the lever about its fulcrum. These upward forces are balanced by the dead weight at the end of the lever.

Sanfoundry Global Education & Learning Series – Machine Dynamics.