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4

The frictional torque transmitted in a flat collar bearing, considering uniform pressure, is (where r₁ and r₂ = External and internal radii of collar respectively)

A. (1/2). μ W (r₁ + r₂)

B. (2/3). μ W (r₁ + r₂)

C. (1/2). μ W [(r₁³ - r₂³)/(r₁² - r₂²)]

D. (2/3). μ W [(r₁³ - r₂³)/(r₁² - r₂²)]

Correct Answer :

D. (2/3). μ W [(r₁³ - r₂³)/(r₁² - r₂²)]


Related Questions

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4

The motion of a shaft in a circular hole is an example of

A. Completely constrained motion

B. Incompletely constrained motion

C. Successfully constrained motion

D. None of these

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4

Under logarithmic decrement, the amplitude of successive vibrations are

A. Constant

B. In arithmetic progression

C. In geometric progression

D. In logarithmic progression

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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

For simple harmonic motion of the of follower, a cosine curve represents

A. Displacement diagram

B. Velocity diagram

C. Acceleration diagram

D. All of the above

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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 component of the acceleration, perpendicular to the velocity of the particle, at the given instant is called

A. Radial component

B. Tangential component

C. Coriolis component

D. None of these

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4

Which of the following disciplines provides study of relative motion between the parts of a machine?

A. Theory of machines

B. Applied mechanics

C. Mechanisms

D. Kinematics

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4

For high 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

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

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 sense of coriolis component 2 ωv is same as that of the relative velocity vector v rotated at

A. 45° in the direction of rotation of the link containing the path

B. 45° in the direction opposite to the rotation of the link containing the path

C. 90° in the direction of rotation of the link containing the path

D. 180° in the direction opposite to the rotation of the link containing the path

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4

In a four-bar chain it is required to give an oscillatory motion to the follower for a continuous rotation of the crank. For the lengths of 50 mm of crank and 70 mm of the follower, determine theoretical maximum length of coupler. The distance between fixed pivots of crank and followers is

A. 95 mm

B. Slightly less than 95 mm

C. Slightly more than 95 mm

D. 45 mm

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4

The unbalanced force due to revolving masses

A. Varies in magnitude but constant in direction

B. Varies in direction but constant in magnitude

C. Varies in magnitude and direction both

D. Constant in magnitude and direction both

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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

Flexible coupling is used because

A. It is easy to disassemble

B. It is easy to engage and disengage

C. It transmits shocks gradually

D. It prevents shock transmission and eliminates stress reversals

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4

In S.H.M., the velocity vector w.r.t. displacement vector

A. Leads by 90°

B. Lags by 90°

C. Leads by 180°

D. Are in phase

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4

A spring controlled governor is said to be stable if the controlling force line when produced intersects the Y-axis

A. At the origin

B. Below the origin

C. Above the origin

D. Any one of these

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4

The centre of gravity of a coupler link in a four bar mechanism will experience

A. No acceleration

B. Only linear acceleration

C. Only angular acceleration

D. Both linear and angular acceleration

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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

Rectilinear motion of piston is converted into rotary by

A. Cross head

B. Slider crank

C. Connecting rod

D. Gudgeon pin

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4

Which of the following is false statement in respect of differences between machine and structure?

A. Machines transmit mechanical work, whereas structures transmit forces

B. In machines, relative motion exists between its members, whereas same does not exist in case of structures

C. Machines modify movement and work, whereas structures modify forces

D. Efficiency of machines as well as structures is below 100%

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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

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

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 method of direct and reverse cranks is used in engines for

A. The control of speed fluctuations

B. Balancing of forces and couples

C. Kinematic analysis

D. Vibration analysis

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4

Shaft revolving in a bearing is the following type of pair

A. Lower pair

B. Higher pair

C. Spherical pair

D. Cylindrical pair

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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 Hartnell governor, the stiffness of the spring is given by (where S1 and S2 = Spring forces exerted on the sleeve at max. and min. radii of rotation, and h = Compression of the spring)

A. (S₁ + S₂)/h

B. (S₁ - S₂)/h

C. (S₁ + S₂)/2h

D. (S₁ - S₂)/2h

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4

In which of the following type of gear train the first gear and the last gear are co-axial.

A. Simple gear train

B. Compound gear train

C. Reverted gear train

D. None of the above

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4

In elliptical trammels

A. All four pairs are turning

B. Three pairs turning and one pair sliding

C. Two pairs turning and two pairs sliding

D. One pair turning and three pairs sliding