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4

Crowning on pulleys helps

A. In increasing velocity ratio

B. In decreasing the slip of the belt

C. For automatic adjustment of belt position so that belt runs centrally

D. Increase belt and pulley life

Correct Answer :

C. For automatic adjustment of belt position so that belt runs centrally


Related Questions

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4

When two links are connected by a pin joint, their instantaneous centre lies

A. On their point of contact

B. At the centre of curvature

C. At the centre of circle

D. At the pin joint

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4

The ratio of the maximum displacement of the forced vibration to the deflection due to the static force, is known as

A. Damping factor

B. Damping coefficient

C. Logarithmic decrement

D. Magnification factor

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4

A reed type tachometer use the principle of

A. Longitudinal vibration

B. Torsional vibration

C. Transverse vibration

D. Damped free vibration

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4

The maximum efficiency of spiral gears is (where θ = Shaft angle, and φ = Friction angle)

A. sin (θ + φ) + 1/ cos (θ - φ) + 1

B. cos (θ - φ) + 1/ sin (θ + φ) + 1

C. cos (θ + φ) + 1/ cos (θ - φ) + 1

D. cos (θ - φ) + 1/ cos (θ + φ) + 1

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4

The periodic time of one oscillation for a simple pendulum is

A. 2π. √(g/l)

B. (1/2π). √(g/l)

C. 2π. √(l/g)

D. (1/2π). √(l/g)

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4

The ratio of maximum fluctuation of speed to the mean speed is called

A. Fluctuation of speed

B. Maximum fluctuation of speed

C. Coefficient of fluctuation of speed

D. None of these

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4

The tractive force is maximum or minimum when the angle of inclination of crank with the line of stroke (θ) is equal to

A. 0° and 90°

B. 90° and 180°

C. 135° and 315°

D. 270° and 360°

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4

A point B on a rigid link AB moves with respect to A with angular velocity ω rad/s. The total acceleration of B with respect to A will be equal to

A. Vector sum of radial component and coriolis component

B. Vector sum of tangential component and coriolis component

C. Vector sum of radial component and tangential component

D. Vector difference of radial component and tangential component

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4

Module of a gear is

A. D/T

B. T/D

C. 2D/T

D. 2T/D

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4

The two elements of a pair are said to form a higher pair, when they

A. Have a surface contact when in motion

B. Have a line or point contact when in motion

C. Are kept in contact by the action of external forces, when in motion

D. Permit relative motion

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4

A thin circular disc is rolling with a uniform linear speed, along a straight path on a plane surface. Which of the following statement is correct in this regard?

A. All points of the disc have the same velocity

B. The centre of the disc has zero acceleration

C. The centre of the disc has centrifugal acceleration

D. The point on the disc making contact with the plane surface has zero acceleration

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4

Transmission angle is the angle between

A. Input link and coupler

B. Input link and fixed link

C. Output link and coupler

D. Output link and fixed link

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4

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

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

B. The two rigid links have no linear velocities relative to each other at the instantaneous centre

C. 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

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

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4

Two systems shall be dynamically equivalent when

A. The mass of two are same

B. C.G. of two coincides

C. M.I. of two about an axis through e.g. is equal

D. All of the above

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4

In a single slider crank chain

A. Each of the four pairs is a turning pair

B. One is a turning pair and three are sliding pairs

C. Two are turning pairs and two are sliding pairs

D. Three are turning pairs and one is a sliding pair

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4

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

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4

Klein's construction can be used to determine acceleration of various parts when the crank is at

A. Inner dead centre

B. Outer dead centre

C. Right angles to the link of the stroke

D. All of the above

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4

When a shaking force is transmitted through the springs, damping becomes detrimental when the ratio of its frequency to the natural frequency is greater than

A. 0.25

B. 0.5

C. 1

D. 2

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4

The example of rolling pair is

A. Bolt and nut

B. Lead screw of a lathe

C. Ball and socket joint

D. Ball bearing and roller bearing

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4

Which of the following statement is correct for involute gears?

A. The interference is inherently absent.

B. The variation in centre distance of shafts increases radial force.

C. A convex flank is always in contact with concave flank.

D. The pressure angle is constant throughout the teeth engagement.

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4

Pulley in a belt drive acts as

A. Cylindrical pair

B. Turning pair

C. Rolling pair

D. Sliding pair

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4

Consider the following mechanisms:
1. Oscillating cylinder engine mechanism
2. Toggle mechanism
3. Radial cylinder engine mechanism
4. Quick return mechanism Which of the above are inversions of slider crank mechanism?

A. 1, 2 and 4

B. 2, 3 and 4

C. 1, 2 and 3

D. 1, 3 and 4

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4

When the axes of the first and last wheels are coaxial, then the train is known as

A. Simple train of wheels

B. Compound train of wheels

C. Reverted gear train

D. Epicyclic gear train

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4

When the two elements of a pair have a surface contact when relative motion takes place and the surface of one element slides over the surface of the other, the pair formed is known as a

A. Lower pair

B. Higher pair

C. Self-closed pair

D. Force-closed pair

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4

In a mechanism, the fixed instantaneous centres are those centres which

A. Remain in the same place for all configurations of the mechanism

B. Vary with the configuration of the mechanism

C. Moves as the mechanism moves, but joints are of permanent nature

D. None of the above

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4

What is the number of instantaneous centres for an eight link mechanism?

A. 15

B. 28

C. 30

D. 8

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4

The Klein's diagram is used when

A. Crank has uniform angular velocity

B. Crank has nonuniform angular velocity

C. Crank has uniform angular acceleration

D. Crank has nonuniform angular acceleration

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4

In the two rotor system as shown in the below figure (I₁ < I₂), a node of vibration is situated

A. Between I₁, and I₂ but nearer I₁

B. Between I₁, and I₂ but nearer to I₂

C. Exactly in the middle of the shaft

D. Nearer to I₁ but outside

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4

A machine mounted on a single coil spring has a period of free vibration of tp . If the spring is cut into four equal parts and placed in parallel and the machine is mounted on them, then the period of free vibration of the new system will become

A. tp /16

B. tp /4

C. 4 tp

D. 16 tp

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4

The maximum frictional force, which comes into play, when a body just begins to slide over the surface of the other body, is known as

A. Static friction

B. Dynamic friction

C. Limiting friction

D. Coefficient of friction