Engineering Questions with Answers - Multiple Choice Questions

# Machine Kinematics MCQ – Gear Trains

1 - Question

In a simple gear train, if the number of idle gears is odd, then the motion of driven gear will
a) be same as that of driving gear
b) be opposite as that of driving gear
c) depend upon the number of teeth on the driving gear
d) none of the mentioned

Explanation: The speed ratio and the train value, in a simple train of gears, is independent of the size and number of intermediate gears. These intermediate gears are called idle gears, as they do not effect the speed ratio or train value of the system.

2 - Question

The train value of a gear train is
a) equal to velocity ratio of a gear train
b) reciprocal of velocity ratio of a gear train
c) always greater than unity
d) always less than unity

Explanation: Train value = Speed of the last driven or follower/Speed of the first driver.

3 - Question

When the axes of first and last gear are co-axial, then gear train is known as
a) simple gear train
b) compound gear train
c) reverted gear train
d) epicyclic gear train

Explanation: When the axes of the first gear (i.e. first driver) and the last gear (i.e. last driven or follower) are co-axial, then the gear train is known as reverted gear train.
When there are more than one gear on a shaft, as shown in Fig. 13.2, it is called a compound train.

4 - Question

In a clock mechanism, the gear train used to connect minute hand to hour hand, is
a) epicyclic gear train
b) reverted gear train
c) compound gear train
d) simple gear train

Explanation: The reverted gear trains are used in automotive transmissions, lathe back gears, industrial speed reducers, and in clocks (where the minute and hour hand shafts are co-axial.

5 - Question

In a gear train, when the axes of the shafts, over which the gears are mounted, move relative to a fixed axis, is called
a) simple gear train
b) compound gear train
c) reverted gear train
d) epicyclic gear train

Explanation: In an epicyclic gear train, the axes of the shafts, over which the gears are mounted, may move relative to a fixed axis.
When the axes of the first gear (i.e. first driver) and the last gear (i.e. last driven or follower) are co-axial, then the gear train is known as reverted gear train.
When there are more than one gear on a shaft, as shown in Fig. 13.2, it is called a compound train of gear.

6 - Question

A differential gear in an automobile is a
a) simple gear train
b) epicyclic gear train
c) compound gear train
d) none of the mentioned

Explanation: The epicyclic gear trains are useful for transmitting high velocity ratios with gears of moderate size in a comparatively lesser space. The epicyclic gear trains are used in the back gear of lathe, differential gears of the automobiles, hoists, pulley blocks, wrist watches etc.

7 - Question

A differential gear in automobilies is used to
a) reduce speed
b) assist in changing speed
c) provide jerk-free movement of vehicle
d) help in turning

Explanation: For turning differential gears are used.

8 - Question

The gear train usually employed in clocks is a
a) reverted gear train
b) simple gear train
c) sun and planet gear
d) differential gear

Explanation: In reverted gear train and last gear train is on the same axis. Such an arrangement has application on speed reducers clocks and machine tools.

9 - Question

The working depth of an involute gear is equal to
b) dedendum

Explanation: Working depth is twice of addendum and whole depth is sum of addendum and dedendum.

10 - Question

Tooth thickness on pitch line of involute gear in terms of module (m) is equal to
a) 1.157 m
b) 1.167 m
c) 2 m
d) 1.5708