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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 anticlockwise 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 :

C. (ω₁ + ω₂) r


Related Questions

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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

The dedendum circle diameter is equal to (where, φ = Pressure angle)

A. Pitch circle dia. × cosφ

B. Addendum circle dia. × cosφ

C. Clearance circle dia. × cosφ

D. Pitch circle dia. × sinφ

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4

In a reciprocating steam engine, which of the following forms a kinematic link?

A. Cylinder and piston

B. Piston rod and connecting rod

C. Crankshaft and flywheel

D. Flywheel and engine frame

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4

When a point at the end of a link moves with constant angular velocity, its acceleration will have

A. Radial component only

B. Tangential component only

C. Coriolis component only

D. Radial and tangential components both

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4

The frictional torque transmitted in a truncated conical pivot bearing, considering uniform pressure, is

A. (1/2). μ W cosecα (r₁ + r₂)

B. (2/3). μ W cosecα (r₁ + r₂)

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

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

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4

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

A. Increases

B. Decreases

C. Remain unaffected

D. First increases and then decreases

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4

Tangential acceleration direction is

A. Along the angular velocity

B. Opposite to angular velocity

C. May be any one of these

D. Perpendicular to angular velocity

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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

In multi V-belt transmission, if one of the belt is broken, we have to change the

A. Broken belt

B. Broken belt and its adjacent belts

C. All the belts

D. There is no need of changing any one as remaining belts can take care of transmission of load

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4

The cam follower generally used in aircraft engines is

A. Knife edge follower

B. Flat faced follower

C. Spherical faced follower

D. Roller follower

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4

With usual notations for different parameters involved, the maximum fluctuations of energy for a flywheel is given by

A. 2ECS

B. ECS/2

C. 2ECS²

D. 2E²CS

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4

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

A. Worm and worm wheel

B. Spur gears

C. Bevel gears

D. Hooke's joint

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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

Which of the following governor is used to drive a gramophone?

A. Watt governor

B. Porter governor

C. Pickering governor

D. Hartnell governor

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4

The coefficient of fluctuation of speed is __________ of maximum fluctuation of speed and the mean speed.

A. Sum

B. Difference

C. Product

D. Ratio

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4

The coriolis component of acceleration is taken into account for

A. Slider crank mechanism

B. Four bar chain mechanism

C. Quick return motion mechanism

D. All of these

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4

In steady state forced vibrations, the amplitude of vibrations at resonance is __________ damping coefficient.

A. Equal to

B. Directly proportional to

C. Inversely proportional to

D. Independent of

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4

When the belt is stationary, it is subjected to some tension known as initial tension. The value of this tension is equal to the

A. Tension in the tight side of the belt

B. Tension in the slack side of the belt

C. Sum of the tensions on the tight side and slack side of the belt

D. Average tension of the tight side and slack side of the belt

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4

In full depth involute system, the smallest number of teeth in a pinion which meshes with rack without interference is

A. 12

B. 16

C. 25

D. 32

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4

The acceleration of a particle at any instant has two components i.e. radial component and tangential component. These two components will be

A. Parallel to each other

B. Perpendicular to each other

C. Inclined at 45°

D. Opposite to each other

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4

The danger of breakage and vibration is maximum

A. Below the critical speed

B. Near the critical speed

C. Above the critical speed

D. None of these

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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

Which type of gearing is used in steering system of an automobile?

A. Rack and pinion

B. Worm and wheel

C. Spiral gears

D. None of the above

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4

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

A. ωR cosθ

B. ω(R - r₁) cosθ

C. ω(R - r₁) sinθ

D. ωr₁ sinθ

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4

Which of the following disciplines provides study of relative motion between the parts of a machine?

A. Theory of machines

B. Applied mechanics

C. Mechanisms

D. Kinematics

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4

In which of the following type of gear train the first gear and the last gear are co-axial.

A. Simple gear train

B. Compound gear train

C. Reverted gear train

D. None of the above

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4

In a cam drive with uniform velocity follower, the sharp corners of the displacement diagram are rounded off at the beginning and at the end of each stroke. This is done

A. Because of difficulty in manufacturing cam profile

B. Because of loose contact of follower with cam surface

C. In order to have acceleration in beginning and retardation at the end of stroke within the finite limits

D. Because the uniform velocity motion is a partial parabolic motion

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4

The Bifilar suspension method is used to determine

A. Natural frequency of vibration

B. Position of balancing weights

C. Moment of inertia

D. Centripetal acceleration

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4

The partial balancing means

A. Balancing partially revolving masses

B. Balancing partially reciprocating masses

C. Best balancing of engines

D. All of these

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4

In a hydrodynamic journal bearing, there is

A. A very thin film of lubricant between the journal and the bearing such that there is contact between the journal and the bearing

B. A thick film of lubricant between the journal and the bearing

C. No lubricant between the journal and the bearing

D. A forced lubricant between the journal and the bearing