Deck 4: Mechanical Engineering: Speed Ratios, Gears, Vibrations, Governors

Question 1

The speed ratio in case of micro gears is

A)Between 1.1 and 5
B)More than 10
C)Less than 1
D)Between 5 and 10
E)1

Answer 1

E

Question 2

For a rational number for the pitch circle diameter and a rational number of teeth on the wheel, the circular pitch will work out to

A)An odd number
B)An even number
C)A rational number
D)An irrational number
E)None of the above

Answer 2

D

Question 3

A swinging field type dynamometer is

A)Torsion dynamometer
B)Vortex type dynamometer
C)Friction dynamometer
D)Electrical dynamometer
E)Transmission type of dynamometer

Answer 3

D

Question 4

Forced vibrations

A)Are followed by free vibrations
B)Are preceded by free vibrations
C)Take place at a frequency more than natural frequency
D)Are independent of natural frequency
E)None of the above

Question 5

A sphere of mass 100 kg moving at 10 m/s overtakes and collides with another sphere of mass 50 kg moving at 3 m/s in the same direction. If the impact is inelastic the velocity of of two masses after impact will be

A)8.33 m/s
B)4.17 m/s
C)Zero
D)13.3 m/s
E)6.67 m/s

Question 6

The critical speed of a shaft is affected by

A)Diameter of the disc
B)Eccentricity
C)Span of shaft
D)(A) and (B) above
E)(A), (B) and (C) above

Question 7

A standard gear cutter No. 3 is marked to cut 35-54 teeth. It implies that

A)The cutter is to be replaced after cutting 54 teeth
B)The cutter will be suitable for gears having 35 to 54 teeth
C)The cutter will be suitable for spur gear teeth cutting only
D)The cutter will provide correct profile for any gear having number of teeth in the range 35 to 54
E)None of the above

Question 8

A kinematic chain requires minimum of

A)3 links and 3 turning pairs
B)4 links and 4 turning pairs
C)3 links and 4 turning pairs
D)2 links and 3 turning pairs
E)4 links and 5 turning pairs

Question 9

Which type of governor is preferred for gramophones?

A)Harting
B)Porter
C)Hartnell
D)Pickering
E)Watt

Question 10

An axial flow fan balanced at one speed often exhibits substantial vibrational effects when operated at other speeds, mainly due to

A)Unbalanced parts of fan
B)Aerodynamic unbalance
C)Primary critical speed effect
D)Secondary critical speed effect
E)Vibration in air

Question 11

In a kinematic chain the minimum number of kinematic pairs required is

A)Five
B)Three
C)Four
D)Two
E)One

Question 12

Which of the following is a spring controlled governor?

A)Harting governor
B)Pickering governor
C)Hartnell governor
D)Wilson hartnell governor
E)All of the above

Question 13

The sum of the tensions when the belt is running on the pulley is

A)Less than the initial tension
B)More than the initial tension
C)More than twise the initial tension
D)Half the initial tension
E)None of the above

Question 14

Klien's construction gives a graphical construction for

A)Velocity polygon
B)Slider crank mechanism
C)Angular accelerations
D)Acceleration polygon
E)Four bar chain mechanism

Question 15

In order that a belt may not run off the pulley

A)It should be properly tightened
B)The centre line of the belt as it approaches the pulley must lie in a plane perpendicular to the axis of that pulley
C)The belt should be provided with frictional material
D)The belt should be provided with a guide
E)None of the above

Question 16

The gears are considered to be operating in medium velocity range if their peripheral velocity lies in the range

A)25-50 m/sec
B)3-15 m/sec
C)15-25 m/sec
D)1-3 m/sec
E)50-75 m/sec

Question 17

Motor cycle shock sbsorbers are generally designed for

A)Resonant damping
B)Light damping
C)Large damping
D)Critical damping
E)Partial damping

Question 18

A point on a link connecting double slider crank chain, traces a

A)Circular path
B)Hoperbolic path
C)Straight line path
D)Parabolic path
E)Elliptical path

Question 19

Velocity of sliding between two mating gear surfaces can be defined as

A)Sum of their angular velocities x distance between pitch point and point of contact.
B)Sum of their angular velocities x distance between their centres of rotation.
C)Sum of their angular velocities x difference between their pitch circle diameters
D)None of these
E)None of the above

Question 20

Identify incorrect statement regarding the flywheel, if any

A)It is provided to minimise vibration of engine
B)It takes care of output fluctuations and controls input accordingly
C)It is provided to control engine speed
D)All above
E)In help in starting engine

Question 21

The number of natural frequencies for three rotor system will be

A)Six
B)Three
C)One
D)Four
E)Two

Question 22

In case of gears, the interference takes place

A)Whenever the forms of the mating teeth are such that contact between them can occur at some place other than along the correct path of contact
B)When gears do not move smoothly in absence of lubrication
C)When the pitch of the gears is not same
D)When the gear teeth are under cut
E)None of the above

Question 23

In case of solid friction, when tan θ =

A)The body A will move over the surface B irrespective of the magnitude of the force F applied on the body
B)tanθ can be equal to
C)tan θcan never be equal to
D)No motion of body A on surface B is possible, irrespective of how large the magnitude of force F applied on the body may be
E)tan θ can be equal to

Question 24

Which of the following is a dead weight type governor?

A)Porter governor
B)Hartnell governor
C)Watt governor
D)All of the above
E)None of the above