THEORY OF MACHINE QUIZ

If ω/ωn = 2, where co is the frequency of excitation and ωn is the natural frequency of vibrations, then the transmissibility of vibration will the

2

0.5

1

1.5

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Which is the false statement about the properties of instantaneous center?

The double center can be denoted either by O2 or O12, but proper selection should be made

At the instantaneous center of rotation, one rigid link rotates instantaneously relative to another for the configuration of mechanism considered

The two rigid links which have no linear velocity relative to each other at this center have the same linear velocity to the third rigid link

The two rigid links have no linear velocities relative to each other at the instantaneous center

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In a four-bar chain it is required to give an oscillatory motion to the follower for a continuous rotation of the crank. For the lengths of 50 mm of crank and 70 mm of the follower, determine theoretical maximum length of coupler. The distance between fixed pivots of crank and followers is

Slightly more than 95 mm

95 mm

45 mm

Slightly less than 95 mm

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In a band and block brake, the ratio of tensions on tight side and slack side of the band is (where μ = Coefficient of friction between the blocks and the drum, θ = Semi-angle of each block subtending at the center of drum, and n = Number of blocks)

T₁/T₂ = [(1 - μ tanθ)/(1 + μ tanθ)]n

T₁/T₂ = [(1 + μ tanθ)/(1 - μ tanθ)]n

T₁/T₂ = μ. θ. n

T₁/T₂ = (μ θ)n

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In a steam engine, the earlier cut-off with a simple slide valve may be obtained by increasing the steam lap and the angle of advance of the eccentric but keeping constant the travel and lead of the valve, this method will

Reduce length of effective stroke of piston

Reduce maximum opening of port to steam

All of the listed here

Cause withdrawing or throttling of steam

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The pressure angle of a cam is the angle between the direction of the follower motion and a normal to the

Pitch circle

Base circle

Pitch curve

Prime circle

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The Ackerman steering gear mechanism is preferred to the Davis steering gear mechanism, because

Both (A) and (B)

Whole of the mechanism in the Ackerman steering gear is on the back of the front wheels

The Ackerman steering gear is most economical

The Ackerman steering gear consists of turning pairs

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To transmit power from one rotating shaft to another whose axes are neither parallel nor intersecting, use?

Worm gear

Spur gear

Bevel gear

Spiral gear

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V-belts are usually used for

Short drives

None of these

Long drives

Long and short drives

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The pressure angle of a cam depends upon

Angle of ascent

Offset between center lines of cam and follower

Lift of follower

All of these

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