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4

A shaft has an attached disc at the centre of its length. The disc has its centre of gravity located at a distance of 2 mm from the axis of the shaft. When the shaft is allowed to vibrate in its natural bow-shaped mode, it has a frequency of vibration of 10 rad/s. When the shaft is rotated at 300 r.p.m., it will whirl with a radius of

A. 2 mm

B. 2.22 mm

C. 2.50 mm

D. 3.0 mm

Correct Answer :

B. 2.22 mm


Related Questions

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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

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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

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

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 absolute acceleration of any point P in a link about center of rotation O is

A. Along PO

B. Perpendicular to PO

C. At 45° to PO

D. None of the above

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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 motion between a pair which takes place in __________ is known as incompletely constrained motion.

A. One direction only

B. Two directions only

C. More than one direction

D. None of these

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4

A slider crank chain consists of following numbers of turning and sliding pairs

A. 1, 3

B. 2, 2

C. 3, 1

D. 4, 0

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4

The lower pair is a

A. Open pair

B. Closed pair

C. Sliding pair

D. Point contact pair

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4

The minimum number of teeth on the pinion which will mesh with any gear without interference for 20° full depth involute teeth will be

A. 12

B. 14

C. 18

D. 24

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4

Which of the following is a higher pair?

A. Belt and pulley

B. Turning pair

C. Screw pair

D. Sliding pair

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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

The maximum fluctuation of energy is the

A. Difference between the maximum and minimum energies

B. Sum of the maximum and minimum energies

C. Variations of energy above and below the mean resisting torque line

D. Ratio of the mean resisting torque to the workdone per cycle

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4

Minimum number of teeth for involute rack and pinion arrangement for pressure angle of 20° is

A. 18

B. 20

C. 30

D. 34

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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

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

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

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4

Which of the following is a lower pair?

A. Ball and socket i

B. Piston and cylinder

C. Cam and follower

D. Both (A) and (B) above

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4

The height of a Watt's governor is

A. Directly proportional to speed

B. Directly proportional to (speed)²

C. Inversely proportional to speed

D. Inversely proportional to (speed)²

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4

The unbalanced primary forces in a reciprocating engine are

A. Balanced completely

B. Balanced partially

C. Balanced by secondary forces

D. Not balanced

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4

Idler pulley is used

A. For changing the direction of motion of the belt

B. For applying tension

C. For increasing velocity ratio

D. All of the above

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4

In a multiple V-belt drive, if one of the belts is broken, then we should replace

A. The broken belt only

B. All the belts

C. The broken belt and the belts on either side of it

D. None of the above

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4

The gear train usually employed in clocks is a

A. Simple gear train

B. Reverted gear train

C. Sun and planet gear

D. Differential gear

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4

The ratio of height of Porter governor (when length of arms and links are equal) to the height of Watt's governor is (where m = Mass of the ball, and M = Mass on the sleeve)

A. m/(m + M)

B. M/(m + M)

C. (m + M)/m

D. (m + M)/M

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4

Power of a governor is the

A. Mean force exerted at the sleeve for a given percentage change of speed

B. Workdone at the sleeve for maximum equilibrium speed

C. Mean force exerted at the sleeve for maximum equilibrium speed

D. None of the above

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4

For low and moderate speed engines, the cam follower should move with

A. Uniform velocity

B. Simple harmonic motion

C. Uniform acceleration and retardation

D. Cycloidal motion

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4

The D-slide valve is also known as

A. Inside admission valve

B. Outside admission valve

C. Piston slide valve

D. None of these

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4

A fixed gear having 200 teeth is in mesh with another gear having 50 teeth. The two gears are connected by an arm. The number of turns made by the smaller gear for one revolution of arm about the centre of bigger gear is

A. 2

B. 4

C. 3

D. None of the above

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4

When the load on the engine increases, it becomes necessary to increase the supply of working fluid and when the load decreases, less working fluid is required. The supply of the working fluid to the engine is controlled by a

A. D-slide valve

B. Governor

C. Meyer's expansion valve

D. Flywheel

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4

Throw of a cam is the maximum distance of the follower from

A. Base circle

B. Pitch circle

C. Root circle

D. Prime circle