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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

Correct Answer :

D. 2


Related Questions

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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

The relation between number of links (l) and number of joints (j) in a kinematic chain is

A. l = (1/2).(j + 2)

B. l = (2/3).(j + 2)

C. l = (3/4).(j + 3)

D. l = j + 4

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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 Klein's method of construction for reciprocating engine mechanism

A. Is a simplified version of instantaneous centre method

B. Utilises a quadrilateral similar to the diagram of mechanism for reciprocating engine

C. Enables determination of coriolis component

D. Is based on the acceleration diagram

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4

The direction of linear velocity of any point on a link with respect to another point on the same link is

A. Parallel to the link joining the points

B. Perpendicular to the link joining the points

C. At 45° to the link joining the points

D. None of the above

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4

In a locomotive, the resultant unbalanced force due to the two cylinders along the line of stroke, is known as

A. Tractive force

B. Swaying couple

C. Hammer blow

D. None of these

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4

Creep in belt drive is due to

A. Weak material of the belt

B. Weak material of the pulley

C. Uneven extensions and contractions of the belt when it passes from tight side to slack side

D. Expansion of the belt

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4

If two moving elements have surface contact in motion, such pair is known as

A. Sliding pair

B. Rolling pair

C. Surface pair

D. Higher pair

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4

The radius of a friction circle for a shaft rotating inside a bearing is (where r = Radius of shaft, and tan φ = Coefficient of friction between the shaft and bearing)

A. r sinφ

B. r cosφ

C. r tanφ

D. (r/2) cosφ

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4

The displacement of the D-slide valve is __________ the steam lap by a distance known as lead of the valve.

A. Greater than

B. Less than

C. Equal to

D. None of these

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4

Longitudinal vibrations are said to occur when the particles of a body moves

A. Perpendicular to its axis

B. Parallel to its axis

C. In a circle about its axis

D. None of these

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4

The frictional torque transmitted in a flat collar bearing, considering uniform wear, is (where r₁ and r₂ = External and internal radii of collar respectively)

A. (1/2) μ W (r₁ + r₂)

B. (2/3) μ W (r₁ + r₂)

C. (1/2) μ W [(r₁³ - r₂³)/(r₁² - r₂²)]

D. (2/3) μ W [(r₁³ - r₂³)/(r₁² - r₂²)]

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4

The tractive force in a locomotive with two cylinders is given by (where c = Fraction of reciprocating parts per cylinder, m = Mass of reciprocating parts, ω = Angular speed of crank, r = Radius of crank, and θ = Angle of inclination of crank to the line of stroke)

A. m.ω².r cosθ

B. c.m.ω².r sinθ

C. (1 - c).m.ω².r (cosθ - sinθ)

D. m.ω².r (cosθ - sinθ)

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4

A Hartnell governor is a

A. Dead weight governor

B. Pendulum type governor

C. Spring loaded governor

D. Inertia governor

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4

A disc is a spinning with an angular velocity ω rad/s about the axis of spin. The couple applied to the disc causing precession will be (where I = Mass moment of inertia of the disc, and ωP = Angular velocity of precession of the axis of spin)

A. (1/2).Iω²

B. Iω²

C. (1/2). I ω ωP

D. I ω ωP

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4

Peaucelliers mechanism has

A. Eight links

B. Six links

C. Four links

D. Twelve links

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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 relative velocity of B with respect to A in a rigid link AB is

A. Parallel to AB

B. Perpendicular to AB

C. Along AB

D. At 45° to AB

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4

When the primary direct crank of a reciprocating engine makes an angle of θ with the line of stroke, then the secondary direct crank will make an angle of _________ with the line of stroke.

A. θ/2

B. θ

C.

D.

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4

Which of the following is an inversion of a double slider crank chain?

A. Oldham's coupling

B. Elliptical trammel

C. Scotch yoke mechanism

D. All of these

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4

The indicator using Watt mechanism is known as

A. Thompson indicator

B. Richard indicator

C. Simplex indicator

D. Thomson indicator

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4

When the sleeve of a Porter governor moves downwards, the governor speed

A. Increases

B. Decreases

C. Remain unaffected

D. First increases and then decreases

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4

A governor is said to be stable, if the

A. Radius of rotation of balls increases as the equilibrium speed decreases

B. Radius of rotation of balls decreases as the equilibrium speed decreases

C. Radius of rotation of balls increases as the equilibrium speed increases

D. Radius of rotation of balls decreases as the equilibrium speed increases

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4

Two pulleys of radii r₁ and r₂ and at distance x apart are connected by means of an open belt drive. The length of the belt is

A. π (r₁ + r₂) + (r₁ + r₂)²/x + 2x

B. π (r₁ + r₂) + (r₁ - r₂)²/x + 2x

C. π (r₁ - r₂) + (r₁ - r₂)²/x + 2x

D. π (r₁ - r₂) + (r₁ + r₂)²/x + 2x

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4

The approximate straight line mechanism is a

A. Four bar linkage

B. 6 bar linkage

C. 8 bar linkage

D. 3 bar linkage

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4

A rotor supported at A and B carries two masses as shown in the below figure. The rotor is

A. Dynamically balanced

B. Statically balanced

C. Statically and dynamically balanced

D. Not balanced

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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

Which of the following is an open pair?

A. Journal bearing

B. Ball and Socket joint

C. Leave screw and nut

D. None of the above

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4

The natural frequency of free longitudinal vibrations is equal to (where m = Mass of the body, s = Stiffness of the body, and δ = Static deflection of the body)

A. 1/2π × √(s/m)

B. 1/2π × √(g/δ)

C. 0.4985/√δ

D. Any one of these

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4

The included angle for the V-belt is usually

A. 10° to 20°

B. 20° to 30°

C. 30° to 40°

D. 60° to 80°