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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

Correct Answer :

C. l = l₁ + l₂.(d₁/d₂)⁴ + l₃.(d₁/d₃)⁴


Related Questions

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4

Which one of the following is an exact straight line mechanism using lower pairs?

A. Watts mechanism

B. Grasshopper mechanism

C. Roberts mechanism

D. Peaucelliers mechanism

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4

Crowning on pulleys helps

A. In increasing velocity ratio

B. In decreasing the slip of the belt

C. For automatic adjustment of belt position so that belt runs centrally

D. Increase belt and pulley life

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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

In a steam engine, the link constitutes a

A. Piston, piston rod and crosshead

B. Connecting rod with big and small end brasses, caps and bolts

C. Crank pin, crankshaft and flywheel

D. All of the 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

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4

The rotating shafts tend to vibrate violently at whirling speeds because

A. The system is unbalanced

B. Bearing centre line coincides with the axis

C. The shafts are rotating at very high speeds

D. Resonance is caused due to the heavy mass of the rotor

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4

When the primary direct crank of a reciprocating engine makes an angle of θ with the line of stroke, then the secondary direct crank will make an angle of _________ with the line of stroke.

A. θ/2

B. θ

C.

D.

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4

The power transmitted by a belt is maximum when the maximum tension in the belt is _________ of centrifugal tension.

A. One-third

B. Two-third

C. Double

D. Three times

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4

For the brake to be self locking, the force P at C shown in the below figure, should

A. Be zero

B. Act in upward direction

C. Act in downward direction

D. None of these

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4

The periodic time is given by (where ω = Angular velocity of the particle in rad/s)

A. ω/2π

B. 2π/ω

C. ω × 2π

D. π/ω

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4

In involute gears, the pressure angle is

A. Dependent on the size of teeth

B. Dependent on the size of gears

C. Always constant

D. Always variable

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4

When the crank is at the inner dead centre, in a reciprocating steam engine, then the velocity of the piston will be

A. Minimum

B. Zero

C. Maximum

D. None of these

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4

Ball and a Socket forms a

A. Turning pair

B. Rolling pair

C. Screw pair

D. Spherical pair

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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

Pitch point of a cam is

A. A point on the pitch curve having minimum pressure angle

B. A point on the pitch curve having maximum pressure angle

C. Any point on the pitch curve

D. Any point on the pitch circle

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4

For dynamic balancing of a shaft

A. The net dynamic force acting on the shaft is equal to zero

B. The net couple due to the dynamic forces acting on the shaft is equal to zero

C. Both (A) and (B)

D. None of the above

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4

The relation between number of pairs (p) forming a kinematic chain and the number of links (l) is

A. l = 2p - 2

B. l = 2p - 3

C. l = 2p - 4

D. l = 2p - 5

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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

The C.G. of a link in any mechanism would experience

A. No acceleration

B. Linear acceleration

C. Angular acceleration

D. Both angular and linear accelerations

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4

The frequency of damped vibrations with viscous damping is ________ the frequency of undamped vibrations.

A. More than

B. Less than

C. Same as

D. None of these

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4

Klein's construction gives a graphic construction for

A. Slider-crank mechanism

B. Velocity polygon

C. Acceleration polygon

D. Four bar chain mechanism

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4

Which of the following statement is correct?

A. The power absorbed in operating the piston valve is less than D-slide valve

B. The wear of the piston valve is less than the wear of the D-slide valve

C. The D-slide valve is also called outside admission valve.

D. All of the above

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4

According to Kennedy's theorem, if three bodies move relatively to each other, their instantaneous centres will lie on a

A. Straight line

B. Parabolic curve

C. Triangle

D. Rectangle

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4

The partial balancing of reciprocating parts in locomotives produces

A. Hammer blow

B. Swaying couple

C. Variation in tractive force along the line of stroke

D. All of the above

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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

In a reciprocating engine, usually __________ of the reciprocating masses are balanced.

A. One-half

B. Two-third

C. Three-fourth

D. Whole

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4

The brake commonly used in railway trains is

A. Shoe brake

B. Band brake

C. Band and block brake

D. Internal expanding brake

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4

It is required to connect two parallel shafts, the distance between whose axes is small and variable. The shafts are coupled by

A. Universal joint

B. Knuckle joint

C. Oldham's coupling

D. Flexible coupling

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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

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