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4

The critical speed of a shaft in revolution per second is __________ as that of natural frequency of transverse vibration.

A. Same

B. Different

C. Unpredictable

D. None of these

Correct Answer :

A. Same


Related Questions

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4

The Grubler's criterion for determining the degrees of freedom (n) of a mechanism having plane motion is (where l = Number of links, and j = Number of binary joints)

A. n = (l -1) - j

B. n = 2(l - 1) - 2j

C. n = 3(l - 1) - 2j

D. n = 4(l - 1) - 3j

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4

Two heavy rotating masses are connected by shafts of lengths l₁, l₂ and l₃ and the corresponding diameters are d₁, d₂ and d₃. This system is reduced to a torsionally equivalent system having uniform diameter d = d₁ of the shaft. The equivalent length of the shaft is

A. (l₁ + l₂ + l₃)/3

B. l = l₁ + l₂.(d₁/d₂)³ + l₂.(d₁/d₃)³

C. l = l₁ + l₂.(d₁/d₂)⁴ + l₃.(d₁/d₃)⁴

D. l₁ + l₂ + l₃

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4

In locomotives, the ratio of the connecting rod length to me crank radius is kept very large in order to

A. Minimise the effect of primary forces

B. Minimise the effect of secondary forces

C. Have perfect balancing

D. To start the locomotive quickly

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4

A mechanism consisting of four links is called a __________ mechanism.

A. Simple

B. Compound

C. Binary

D. None of these

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4

The primary unbalanced force is maximum _________ in one revolution of the crank.

A. Twice

B. Four times

C. Eight times

D. Sixteen times

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4

The ratio of maximum fluctuation of speed to the mean speed is called

A. Fluctuation of speed

B. Maximum fluctuation of speed

C. Coefficient of fluctuation of speed

D. None of these

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4

According to Kennedy's theorem, if three bodies have plane motions, their instantaneous centers lie on

A. A triangle

B. A point

C. Two lines

D. A straight line

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4

Creep in belt drive is due to

A. Material of the pulley

B. Material of the belt

C. Larger size of the driver pulley

D. Uneven extensions and contractions due to varying tension

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4

Angle of descent of cam is defined as the angle

A. During which the follower returns to its initial position

B. Of rotation of the cam for a definite displacement of the follower

C. Through which the cam rotates during the period in which the follower remains in the highest position

D. Moved by the cam from the instant the follower begins to rise, till it reaches its highest position

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4

Maximum fluctuation of energy in a flywheel is equal to [where I = Mass moment of inertia of the flywheel, E = Maximum fluctuation of energy, CS = Coefficient of fluctuation of speed, and ω = Mean angular speed = (ω₁ + ω₂)/2]

A. I.ω.(ω₁ - ω₂)

B. I.ω².CS

C. 2.E.CS

D. All of these

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4

An imaginary circle which by pure rolling action, gives the same motion as the actual gear, is called

A. Addendum circle

B. Dedendum circle

C. Pitch circle

D. Clearance circle

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4

The secondary unbalanced force is maximum __________ in one revolution of the crank.

A. Two times

B. Four times

C. Eight times

D. Sixteen times

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4

The acceleration of the reciprocating roller follower when it has contact with the straight flanks of the tangent cam, is given by

A. ω². (r₁ r₂). (1 - cos² θ)

B. ω². (r₁ + r₂). (1 + cos² θ)

C. ω². (r₁ + r₂). [(2 - cos² θ)/cos³ θ]

D. ω². (r₁ - r₂). (1 - sin² θ)

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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

The Klein's diagram is useful to find

A. Displacement of various parts

B. Velocity of various parts

C. Acceleration of various parts

D. Angular acceleration of various parts

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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

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

Which of the following is a higher pair?

A. Turning pair

B. Screw pair

C. Belt and pulley

D. None of the above

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4

The gears are termed as medium velocity gears, if their peripheral velocity is

A. 1-3 m/s

B. 3-15 m/s

C. 15-30 m/s

D. 30-50 m/s

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4

The essential condition of placing the two masses, so that the system becomes dynamically equivalent, is (where l₁ and l₂ = Distance of two masses from the centre of gravity of the body, and kG = Radius of gyration of the body)

A. l₁ = kG

B. l₂ = kG

C. l₁l₂ = kG

D. l₁l₂ = kG²

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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 maximum value of the pressure angle in case of cam is kept as

A. 10°

B. 14°

C. 20°

D. 30°

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4

Scotch yoke mechanism is used to generate

A. Sine functions

B. Square roots

C. Logarithms

D. Inversions

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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 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

When the speed of the engine fluctuates continuously above and below the mean speed, the governor is said to be

A. Stable

B. Unstable

C. Isochronous

D. Hunt

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4

Which one of the following can completely balance several masses revolving in different planes on a shaft?

A. A single mass in different planes

B. Two masses in any two planes

C. A single mass in one of the planes of the revolving masses

D. Two equal masses in any two planes

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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

The Ackerman steering gear mechanism is preferred to the Davis steering gear mechanism, because

A. Whole of the mechanism in the Ackerman steering gear is on the back of the front wheels

B. The Ackerman steering gear consists of turning pairs

C. The Ackerman steering gear is most economical

D. Both (A) and (B)

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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