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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

Correct Answer :

A. r sinφ


Related Questions

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4

Angle of action of cam is defined as the angle

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

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

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

D. Moved by the cam from beginning of ascent to the termination of descent

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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

Which type of gear train is used in clock mechanism to join hour hand and minute hand?

A. Simple gear train

B. Compound gear train

C. Reverted gear train

D. Epicyclic gear train

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4

A mass of 1 kg is attached to the end of a spring with a stiffness of 0.7 N/mm. The critical damping coefficient of this system is

A. 1.4 N-s/m

B. 18.52 N-s/m

C. 52.92 N-s/m

D. 529.2 N-s/m

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4

In a single slider crank chain

A. Each of the four pairs is a turning pair

B. One is a turning pair and three are sliding pairs

C. Two are turning pairs and two are sliding pairs

D. Three are turning pairs and one is a sliding pair

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4

The velocity of any point in mechanism relative to any other point on the mechanism on velocity polygon is represented by the line

A. Joining the corresponding points

B. Perpendicular to line as per (A)

C. Not possible to determine with these data

D. At 45° to line as per (A)

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4

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

A. ω²r. (n + 1)/n

B. ω²r. (n - 1)/n

C. ω²r. n/(n + 1)

D. ω²r. n/(n - 1)

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4

Transmission angle is the angle between

A. Input link and coupler

B. Input link and fixed link

C. Output link and coupler

D. Output link and fixed link

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4

Oldhams coupling is an inversion of the kinematic chain used in

A. Whitworth quick return mechanism

B. Elliptical trammels

C. Rotary engine

D. Universal joint

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4

Cam size depends upon

A. Base circle

B. Pitch circle

C. Prime circle

D. Outer circle

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4

The condition for correct steering of a Davis steering gear is (where α = Angle of inclination of the links to the vertical)

A. sinα = b/c

B. cosα = c/b

C. tanα = c/2b

D. cotα = c/2b

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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

Pulley in a belt drive acts as

A. Cylindrical pair

B. Turning pair

C. Rolling pair

D. Sliding pair

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4

The number of links and instantaneous centers in a reciprocating engine mechanism are

A. 4, 4

B. 4, 5

C. 5, 4

D. 4, 6

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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

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 point on a link connecting double slider crank chain traces a

A. Ellipse

B. Circle

C. Parabola

D. Hyperbola

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4

A motor car moving at a certain speed takes a left turn in a curved path. If the engine rotates in the same direction as that of wheels, men due to centrifugal forc

A. The reaction on me inner wheels increases and on the outer wheels decreases

B. The reaction on the outer wheels increases and on the inner wheels decreases

C. The reaction on the front wheels increases and on the rear wheels decreases

D. The reaction on the rear wheels increases and on the front wheels decreases

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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

The velocity of piston in a reciprocating steam engine is given by (where ω = Angular velocity of crank, r = Radius of crank pin circle, θ = Angle turned by crank from inner dead centre, and n = Ratio of length of connecting rod to the radius of crank)

A. ωr [sin θ + (sin 2θ/n)]

B. ωr [cos θ + (cos 2θ/n)]

C. ω²r [sin θ + (sin 2θ/n)]

D. ω²r [cos θ + (cos 2θ/n)]

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4

When the body is suspended at the point of suspension, its periodic time and frequency will be ________ as compared to the body suspended at the point of percussion.

A. Same

B. Two times

C. Four times

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 magnitude of linear velocity of a point B on a link AB relative to point A is (Where ω = Angular velocity of the link AB)

A. ω × AB

B. ω × (AB)²

C. ω² × AB

D. (ω × AB)²

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4

The swaying couple is maximum or minimum when the angle of inclination of the crank to the line of stroke (θ) is equal to

A. 90° and 180°

B. 45° and 225°

C. 180° and 270°

D. 270° and 360°

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4

Oldham's coupling is the

A. Second inversion of double slider crank chain

B. Third inversion of double slider crank chain

C. Second inversion of single slider crank chain

D. Third inversion of slider crank chain

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4

A spring controlled governor is found unstable. It can be made stable by

A. Increasing the spring stiffness

B. Decreasing the spring stiffness

C. Increasing the ball mass

D. Decreasing the ball mass

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4

Efficiency of a screw jack is given by

A. tan (α + φ)/tanα

B. tanα/tan (α +φ)

C. tan (α - φ)/tanα

D. tanα/tan (α - φ)

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4

The inversion of a mechanism is

A. Changing of a higher pair to a lower pair

B. Turning its upside down

C. Obtained by fixing different links in a kinematic chain

D. Obtained by reversing the input and output motion

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4

In order to facilitate starting of locomotive in any position, the cranks of a locomotive with two cylinders, are placed at

A. 45° to each other

B. 90° to each other

C. 120° to each other

D. 180° to each other

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4

For an involute gear, the ratio of base circle radius and pitch circle radius is equal to

A. sinφ

B. cosφ

C. secφ

D. cosecφ