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What is the correct answer?

4

The Whitworth quick return motion mechanism is formed in a slider crank chain when the

A. Coupler link is fixed

B. Longest link is a fixed link

C. Slider is a fixed link

D. Smallest link is a fixed link

Correct Answer :

A. Coupler link is fixed


Related Questions

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4

Coriolis component is encountered in

A. Quick return mechanism of shaper

B. Four bar chain mechanism

C. Slider crank mechanism

D. Both (A) and (C) above

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4

The Whitworth quick return motion mechanism is formed in a slider crank chain when the

A. Coupler link is fixed

B. Longest link is a fixed link

C. Slider is a fixed link

D. Smallest link is a fixed link

What is the correct answer?

4

The main disadvantage of the sliding pair is that it is

A. Bulky

B. Wears rapidly

C. Difficult to manufacture

D. Both (A) and (B) above

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4

Coriolis component acts

A. Perpendicular to sliding surfaces

B. Along sliding surfaces

C. Somewhere in between above two

D. None of the above

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4

Lower pairs are those which have

A. Point or line contact between the two elements when in motion

B. Surface contact between the two elements when in motion

C. Elements of pairs not held together mechanically

D. Two elements that permit relative motion

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4

A simple spring-mass vibrating system has a natural frequency of fn. If the spring stiffness is halved and the mass is doubled, then the natural frequency will become

A. fn/2

B. 2 fn

C. 4 fn

D. 8 fn

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4

A mechanism is an assemblage of

A. Two links

B. Three links

C. Four or more than four links

D. All of these

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4

The displacement of a flat faced follower when it has contact with the flank of a circular arc cam, is given by (where R = Radius of flank, r₁ = Minimum radius of the cam, and θ = Angle turned through by the cam)

A. R (1 - cosθ)

B. (R - r₁) (1 - cosθ)

C. R (1 - sinθ)

D. (R - r₁) (1 - sinθ)

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4

Kinematic pairs are those which have

A. Point or line contact between the two elements when in motion

B. Surface contact between the two elements when in motion

C. Elements of pairs not held together mechanically

D. Two elements that permit relative motion

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4

A body will begin to move down an inclined plane, if the angle of inclination of the plane is ________ the angle of friction.

A. Equal to

B. Less than

C. Greater than

D. None of these

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4

The velocity of the reciprocating roller follower when it has contact with the straight flanks of the tangent cam, is given by (where ω = Angular velocity of the cam shaft)

A. ω (r₁ r₂) sinθ

B. ω (r₁ + r₂) sinθ sec2θ

C. ω (r₁ r₂) cosθ

D. ω (r₁ + r₂) cosθ cosec2θ

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4

The secondary unbalanced force is __________ the primary unbalanced force.

A. One-half

B. Two-third

C. n times

D. 1/n times

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4

A friction circle is a circle drawn when a journal rotates in a bearing. Its radius depends upon the coefficient of friction and the

A. Magnitude of the forces on journal

B. Angular velocity of journal

C. Clearance between journal and bearing

D. Radius of journal

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4

In a four bar chain or quadric cycle 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

In higher pair, the relative motion is

A. Purely turning

B. Purely sliding

C. Purely rotary

D. Combination of sliding and turning

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4

In vibration isolation system, if ω/ωn < 2, then for all values of damping factor, the transmissibility will be (where ω = Angular speed of the system, ωn = Natural frequency of vibration of the system)

A. Less than unity

B. Equal to unity

C. Greater than unity

D. Zero

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4

The dynamic friction is the friction experienced by a body, when the body

A. Is in motion

B. Is at rest

C. Just begins to slide over the surface of the other body

D. None of the above

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4

The periodic time of a compound pendulum is __________ when the distance between the point of suspension and the centre of gravity is equal to the radius of gyration of the body about its centre of gravity.

A. Zero

B. Minimum

C. Maximum

D. None of these

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4

Open pairs are those which have

A. Point or line contact between the two elements when in motion

B. Surface contact between the two elements when in motion

C. Elements of pairs not held together mechanically

D. Two elements that permit relative motion

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4

Which of the following disciplines provides study of the relative motion between the parts of a machine and the forces acting on the parts?

A. Theory of machines

B. Applied mechanics

C. Mechanisms

D. Kinetics

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4

The primary unbalanced force due to inertia of reciprocating parts in a reciprocating engine is given by (where m = Mass of reciprocating parts, ω = Angular speed of crank, r = Radius of crank, θ = Angle of inclination of crank with the line of stroke, and n = Ratio of the length of connecting rod to radius of crank)

A. m.ω².r sinθ

B. m.ω².r cosθ

C. m.ω².r (sin 2θ/n)

D. m.ω².r (cos 2θ/n)

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4

For S.H.M. cam, the acceleration of the follower at the ends of the stroke and aimed stroke respectively, is

A. Maximum and zero

B. Zero and maximum

C. Minimum and maximum

D. Zero and minimum

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4

A torsional system with discs of moment of inertia I₁ and I₂ as shown in the below figure, is gear driven such that the ratio of speed of shaft B to shaft A is 'G'. Neglecting the inertia of gears, the equivalent inertia of disc on shaft B at the speed of shaft A is equal to

A. G.I₂

B. G².I₂

C. I₂/G

D. I₂/G²

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4

An exact straight line motion mechanism is a

A. Scott-Russell's mechanism

B. Hart's mechanism

C. Peaucellier's mechanism

D. All of these

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4

The direction of Coriolis component of acceleration is the direction

A. Of relative velocity vector for the two coincident points rotated by 90° in the direction of the angular velocity of the rotation of the link

B. Along the centripetal acceleration

C. Along tangential acceleration

D. Along perpendicular to angular velocity

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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

In Meyer's expansion valve, the main valve is driven by an eccentric having an angle of advance from

A. 10°-15°

B. 15°-25°

C. 25°-30°

D. 30°-40°

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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

A Hartnell governor has its controlling force (Fc) given by Fc = ar + b, where r is the radius of rotation and a and b are constants. The governor becomes isochronous when

A. a is +ve and b = 0

B. a = 0 and b is +ve

C. a is +ve and b is -ve

D. a is +ve and b is also +ve

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4

Efficiency of a screw jack is given by

A. tan (α + φ)/tanα

B. tanα/tan (α +φ)

C. tan (α - φ)/tanα

D. tanα/tan (α - φ)