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4

The two links OA and OB are connected by a pin joint at O. If the link OA turns with angular velocity ω₁ rad/s in the clockwise direction and the link OB turns with angular velocity ω₂ rad/s in the clockwise direction, then the rubbing velocity at the pin joint O is (where r = Radius of the pin at O)

A. ω₁.ω₂.r

B. (ω₁ - ω₂)r

C. (ω₁ + ω₂)r

D. (ω₁ - ω₂)2r

Correct Answer :

B. (ω₁ - ω₂)r


Related Questions

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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 maximum velocity of a particle moving with simple harmonic motion is

A. ω

B. ωr

C. ω²r

D. ω/r

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4

The number of links and instantaneous centers in a reciprocating engine mechanism are

A. 4, 4

B. 4, 5

C. 5, 4

D. 4, 6

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4

In a Hartnell governor, the lift of the sleeve is given by (where r₁ and r₂ = Max. and min. radii of rotation, x = Length of ball arm of the lever, and y = Length of sleeve arm of the lever)

A. (r₁ + r₂) (y/x)

B. (r₁ + r₂) (x/y)

C. (r₁ - r₂) (y/x)

D. (r₁ - r₂) (x/y)

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4

The maximum or minimum value of the swaying couple is

A. ± c.m.ω².r

B. ± a (1 - c) m.ω².r

C. ± (a/√2) (1 - c) m.ω².r

D. ± 2a (1 - c) m.ω².r

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4

The load cup of a screw jack is made separate from the head of the spindle to

A. Enhance the load carrying capacity of the jack

B. Reduce the effort needed for lifting the working load

C. Reduce the value of frictional torque required to be countered for lifting the load

D. Prevent the rotation of load being lifted

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4

To obviate axial thrust, following gear drive is used

A. Double helical gears having opposite teeth

B. Double helical gears having identical teeth

C. Single helical gear in which one of the teeth of helix angle a is more

D. Mutter gears

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4

The advantage of the piston valve over the slide valve is that in the former case

A. Wear is less

B. Power absorbed is less

C. Both wear and power absorbed are low

D. The pressure developed being high provides tight sealing

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4

Sensitiveness of the governor is defined as the ratio of the

A. Mean speed to the maximum equilibrium speed

B. Mean speed to the minimum equilibrium speed

C. Difference of the maximum and minimum equilibrium speeds to the mean speed

D. Sum of the maximum and minimum equilibrium speeds to the mean speed

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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

The maximum fluctuation of speed is the

A. Difference of minimum fluctuation of speed and the mean speed

B. Difference of the maximum and minimum speeds

C. Sum of maximum and minimum speeds

D. Variations of speed above and below the mean resisting torque line

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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

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

Transmission of power from the engine to the rear axle of an automobile is by means of

A. Compound gears

B. Worm and wheel method

C. Hooke's joint

D. Crown gear

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4

Hammer blow

A. Is the maximum horizontal unbalanced force caused by the mass provided to balance the reciprocating masses.

B. Is the maximum vertical unbalanced force caused by the mass added to balance the reciprocating masses

C. Varies as the square root of the speed

D. Varies inversely with the square of the speed

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4

In a four stroke I.C. engine, the turning moment during the compression stroke is

A. Positive throughout

B. Negative throughout

C. Positive during major portion of the stroke

D. Negative during major portion of the stroke

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4

In order to give a complete secondary balance of a multi-cylinder inline engine,

A. The algebraic sum of the secondary forces must be equal to zero

B. The algebraic sum of the couples about any point in the plane of the secondary forces must be equal to zero

C. Both (A) and (B)

D. None of these

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4

The acceleration of a flat-faced follower when it has contact with the flank of a circular arc cam, is given by

A. ω² R cosθ

B. ω² (R - r₁) cosθ

C. ω² (R - r₁) sinθ

D. ω² r₁ sinθ

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4

Typewriter constitutes

A. Machine

B. Structure

C. Mechanism

D. Inversion

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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

Bifilar suspension method is used to find the

A. Angular acceleration of the body

B. Moment of inertia of the body

C. Periodic time of the body

D. Frequency of vibration of the body

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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

When a slider moves on a fixed link having curved surface, 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 total number of instantaneous centres for a mechanism consisting of n links are

A. n/2

B. n

C. n - 1

D. n(n - 1)/2

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4

A chain comprises of 5 links having 5 joints. Is it kinematic chain?

A. Yes

B. No

C. It is a marginal case

D. Data are insufficient to determine it

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4

A system in dynamic balance implies that

A. The system is critically damped

B. There is no critical speed in the system

C. The system is also statically balanced

D. There will absolutely no wear of bearings

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4

A cam with a roller follower would constitute following type of pair

A. Lower pair

B. Higher pair

C. Open pair

D. Close pair

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4

A mechanism __________ for transmitting or transforming motion.

A. Can be used

B. Cannot be used

C. Unpredictable

D. None of these

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4

Kinematic pairs are those which have two elements that

A. Have line contact

B. Have surface contact

C. Permit relative motion

D. Are held together

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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