Mechanical Engineering - Theory of machines

6. 

If ω/ωn is very high for a body vibrating under steady state vibrations, the phase angle for all values of damping factors, will tend to approach

A.
B. 90°
C. 180°
D. 360°

Answer: Option C

Explanation:

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7. 

In a circular arc cam with roller follower, the acceleration in any position of the lift will depend only upon

A. total lift, total angle of lift, minimum radius of cam and cam speed
B. radius of circular arc, cam speed, location of centre of circular arc and roller diameter
C. mass of cam follower linkage, spring stiffness and cam speed
D. total lift, centre of gravity of the cam and cam speed

Answer: Option A

Explanation:

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8. 

When the relation between the controlling force (Fc) and radius of rotation (r) for a spring controlled governor is Fc = ar + b, then the governor will be

A. stable
B. unstable
C. isochronous
D. none of these

Answer: Option B

Explanation:

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9. 

The factor which affects the critical speed of a shaft is

A. diameter of disc
B. span of shaft
C. eccentricity
D. all of these

Answer: Option D

Explanation:

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10. 

The partial balancing of reciprocating parts in locomotives produces

A. hammer blow
B. swaying couple
C. variation in tractive force along the line of stroke
D. all of the above

Answer: Option D

Explanation:

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