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4

The frictional torque transmitted in a flat pivot bearing, assuming uniform wear, is (Where μ = Coefficient of friction, W=Load over the bearing, R=Radius of bearing)

A. μwr

B. ¾μWR

C. (2/3) μWR

D. ½μWR

Correct Answer :

D. ½μWR


Related Questions

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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

Balancing of rotating and reciprocating parts of an engine is necessary when it runs at

A. Slow speed

B. Moderate speed

C. Highs peed

D. Any one of these

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4

The approximate straight line mechanism is a

A. Four bar linkage

B. 6 bar linkage

C. 8 bar linkage

D. 3 bar linkage

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4

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

A. 0° and 90°

B. 0° and 180°

C. 90° and 180°

D. 180° and 360°

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4

In a multiple V-belt drive, when a single belt is damaged, it is preferable to change the complete set to

A. Reduce vibration

B. Reduce slip

C. Ensure uniform loading

D. Ensure proper alignment

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4

Which of the following is a lower pair?

A. Ball and socket i

B. Piston and cylinder

C. Cam and follower

D. Both (A) and (B) above

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4

A circle passing through the pitch point with its center at the center of cam axis is known as

A. Pitch circle

B. Base circle

C. Prime circle

D. Outer circle

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4

Which of the following statement is correct as regard to the difference between a machine and a structure?

A. The parts of a machine move relative to one another, whereas the members of a structure do not move relative to one another

B. The links of a machine may transmit both power and motion, whereas the members of a structure transmit forces only

C. A machine transforms the available energy into some useful work, whereas in a structure no energy is transformed into useful work

D. All of the above

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4

The included angle for the V-belt is usually

A. 10° to 20°

B. 20° to 30°

C. 30° to 40°

D. 60° to 80°

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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

The minimum periodic time of a compound pendulum is

A. (1/2π). √(kG/g)

B. (1/2π). √(2kG/g)

C. 2π. √(kG/g)

D. 2π. √(2kG/g)

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4

When two pulleys are connected by means of a cross belt drive, then both the pulleys will rotate in __________ directions.

A. Same

B. Opposite

C. Perpendicular

D. None of these

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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

Frequency of vibrations is usually expressed in

A. Number of cycles per hour

B. Number of cycles per minute

C. Number of cycles per second

D. None of these

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4

A body in motion will be subjected to coriolis acceleration when that body is

A. In plane rotation with variable velocity

B. In plane translation with variable velocity

C. In plane motion which is a resultant of plane translation and rotation

D. Restrained to rotate while sliding over another body

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4

ABCD is a four bar mechanism in which AB = 310 mm and CD = 450 mm. AB and CD are both perpendicular to the fixed link AD, as shown in the below figure. If the velocity of B at this condition is v. Then the velocity of C is

A. v

B. (2/3). v

C. (3/2). v

D. (9/4). v

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4

There are six gears A, B, C, D, E and F in a compound train. The numbers of teeth in the gears are 20, 60, 30, 80, 25 and 75 respectively. The ratio of angular speeds of the driven (F) to the driver (A) of the drive is

A. 1/24

B. 1/8

C. 4/15

D. 12

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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

In a system subjected to damped forced vibrations, the ratio of maximum displacement to the static deflection is known as

A. Critical damping ratio

B. Damping factor

C. Logarithmic decrement

D. Magnification factor

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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

Which of the following is an example of sliding pair?

A. Piston and cylinder of a reciprocating steam engine

B. Shaft with collars at both ends fitted into a circular hole

C. Lead screw of a lathe with nut

D. Ball and a socket joint

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4

The Scott-Russell mechanism consists of

A. Sliding and turning pairs

B. Sliding and rotary pairs

C. Turning and rotary pairs

D. Sliding pairs only

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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

Pitch point on a cam is

A. Any point on pitch curve

B. The point on cam pitch curve having the maximum pressure angle

C. Any point on pitch circle

D. The point on cam pitch curve having the minimum pressure angle

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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

When a point at the end of a link moves with constant angular velocity, its acceleration will have

A. Radial component only

B. Tangential component only

C. Coriolis component only

D. Radial and tangential components both

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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

Pulley in a belt drive acts as

A. Cylindrical pair

B. Turning pair

C. Rolling pair

D. Sliding pair

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4

In Meyer's expansion valve, the expansion valve is driven by an eccentric having an angle of advance from

A. 50°-60°

B. 60°-70°

C. 70°-80°

D. 80°-90°

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4

A point B on a rigid link AB moves with respect to A with angular velocity ω rad/s. The total acceleration of B with respect to A will be equal to

A. Vector sum of radial component and coriolis component

B. Vector sum of tangential component and coriolis component

C. Vector sum of radial component and tangential component

D. Vector difference of radial component and tangential component