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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

Correct Answer :

A. Shoe brake


Related Questions

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4

A single degree of freedom system is given by, m × (d²x/dt²) + c × (dx/dt) + sx = F.cosω.t with usual notations. It represents

A. Free vibration with damping

B. Free vibration without damping

C. Forced vibration with damping

D. Forced vibration without damping

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4

Which of the following statement is correct?

A. The primary unbalanced force is less than the secondary unbalanced force.

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

C. The unbalanced force due to reciprocating masses varies in magnitude and direction both.

D. The magnitude of swaying couple in locomotives is inversely proportional to the distance between the two cylinder centre lines

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4

In the below figure, PC is the connecting rod and OC is the crank making an angle θ with the line of stroke PO and rotates with uniform angular velocity at ω rad/s. The Klien's acceleration diagram for determining the acceleration of the piston P is shown by quadrilateral CQNO, if N coincides with O, then

A. Acceleration and velocity of the piston P is zero

B. Acceleration and velocity of the piston P is maximum

C. Acceleration of the piston P is zero and its velocity is maximum

D. Acceleration of the piston P is maximum and its velocity is zero

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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

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

In a radial cam, the follower moves

A. In a direction perpendicular to the cam axis

B. In a direction parallel to the cam axis

C. In any direction irrespective of the cam axis

D. Along the cam axis

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4

The factional torque for square thread at the mean radius r while raising load W is given by

A. T = W.r tan(φ - α)

B. T = W.r tan(φ + α)

C. T = W.r tanα

D. T = W.r tanφ

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4

The main disadvantage of the sliding pair is that it is

A. Bulky

B. Wears rapidly

C. Difficult to manufacture

D. Both (A) and (B) above

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4

The secondary unbalanced force is maximum when the angle of inclination of the crank with the line of stroke is

A. 0° and 90°

B. 180° and 360°

C. Both (A) and (B)

D. None of these

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4

The number of links in pantograph mechanism is equal to

A. 2

B. 3

C. 4

D. 5

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4

In a band and block brake, the ratio of tensions on tight side and slack side of the band is (where μ = Coefficient of friction between the blocks and the drum, θ = Semi-angle of each block subtending at the centre of drum, and n = Number of blocks)

A. T₁/T₂ = μ. θ. n

B. T₁/T₂ = [(1 - μ tanθ)/(1 + μ tanθ)]n

C. T₁/T₂ = (μ θ)n

D. T₁/T₂ = [(1 + μ tanθ)/(1 - μ tanθ)]n

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4

The magnitude of velocities of the points on a rigid link is

A. Directly proportional to the distance from the points to the instantaneous centre and is parallel to the line joining the point to the instantaneous centre

B. Directly proportional to the distance from the points to the instantaneous centre and is perpendicular to the line joining the point to the instantaneous centre

C. Inversely proportional to the distance from the points to the instantaneous centre and is parallel to the line joining the point to the instantaneous centre

D. Inversely proportional to the distance from the points to the instantaneous centre and is perpendicular to the line joining the point to the instantaneous centre

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4

In under damped vibrating system, the amplitude of vibration

A. Decreases linearly with time

B. Increases linearly with time

C. Decreases exponentially with time

D. Increases exponentially with time

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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

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4

If the radius of gyration of a compound pendulum about an axis through e.g. is more, then its frequency of oscillation will be

A. Less

B. More

C. Same

D. Data are insufficient to determine same

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4

In a flat collar pivot bearing, the moment due to friction is proportional to

A. (r₁² - r₂²)/(r₁ - r₂)

B. (r₁² - r₂²)/(r₁ + r₂)

C. (r₁³ - r₂³)/(r₁² - r₂²)

D. (r₁³ - r₂³)/(r₁ - r₂)

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4

A foot step bearing and rotor of a vertical turbine form examples of

A. Incompletely constrained motion

B. Partially constrained motion

C. Completely constrained motion

D. Successfully constrained motion

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4

The tractive force in a locomotive with two cylinders is given by (where c = Fraction of reciprocating parts per cylinder, m = Mass of reciprocating parts, ω = Angular speed of crank, r = Radius of crank, and θ = Angle of inclination of crank to the line of stroke)

A. m.ω².r cosθ

B. c.m.ω².r sinθ

C. (1 - c).m.ω².r (cosθ - sinθ)

D. m.ω².r (cosθ - sinθ)

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4

A combination of kinematic pairs, joined in such a way that the relative motion between the links is completely constrained, is called a

A. Structure

B. Mechanism

C. Kinematic chain

D. Inversion

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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 transmissibility, for all values of damping factor, will be less than unity, if ω/ωn is

A. Equal to 1

B. Less than 2

C. Equal to 2

D. Greater than 2

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4

3.The retardation of a flat faced follower when it has contact at the apex of the nose of a circular arc cam, is given by (where OQ = Distance between the centre of circular flank and centre of nose)

A. ω² × OQ

B. ω² × OQ sinθ

C. ω² × OQ cosθ

D. ω² × OQ tanθ

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4

In a vibrating system, if the actual damping coefficient is 40 N/m/s and critical damping coefficient is 420 N/m/s, then logarithmic decrement is equal to

A. 0.2

B. 0.4

C. 0.6

D. 0.8

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4

A circular bar moving in a round hole is an example of

A. Incompletely constrained motion

B. Partially constrained motion

C. Completely constrained motion

D. Successfully constrained motion

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4

A kinematic chain is known as a mechanism when

A. None of the links is fixed

B. One of the links is fixed

C. Two of the links are fixed

D. None of these

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4

A watt's governor can work satisfactorily at speeds from

A. 60 to 80 r.p.m.

B. 80 to 100 r.p.m.

C. 100 to 200 r.p.m.

D. 200 to 300 r.p.m.

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4

For the same lift and same angle of ascent, a smaller base circle will give

A. A small value of pressure angle

B. A large value of pressure angle

C. There is no such relation with pressure angle

D. Something else

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4

If ω/ωn = 2, where co is the frequency of excitation and ωn is the natural frequency of vibrations, then the transmissibility of vibration will the

A. 0.5

B. 1

C. 1.5

D. 2

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4

A thin circular disc is rolling with a uniform linear speed, along a straight path on a plane surface. Which of the following statement is correct in this regard?

A. All points of the disc have the same velocity

B. The centre of the disc has zero acceleration

C. The centre of the disc has centrifugal acceleration

D. The point on the disc making contact with the plane surface has zero acceleration

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4

Rectangular bar in a rectangular hole is the following type of pair

A. Completely constrained motion

B. Partially constrained motion

C. Incompletely constrained motion

D. Freely constrained motion