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Antifriction bearings are

A. Sleeve bearings

B. Hydrodynamic bearings

C. Thin lubricated bearings

D. None of the above

Correct Answer :

D. None of the above


Related Questions

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During hot working of metals,

A. Porosity of the metal is largely eliminated

B. Grain structure of the metal is refined

C. Mechanical properties are improved due of refinement of grains

D. All of the above

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4

Which of the following is a permanent fastening?

A. Bolts

B. Keys

C. Cotters

D. Rivets

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4

The standard length of the shaft is

A. 6 m

B. 5 m

C. 7 m

D. All of these

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4

When carbon in the cast iron is principally in the form of graphite, the cast iron will be of

A. Brown colour

B. Yellow colour

C. White colour

D. Grey colour

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4

In order to have a connecting rod equally strong in buckling about X-axis and Y-axis, the moment of inertia about X-axis should be __________ the moment of inertia about Y-axis.

A. Equal to

B. Twice

C. Three times

D. Four times

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4

A steel containing __________ 0.8% carbon is known as hypoeutectoid steel.

A. Equal to

B. Less than

C. Greater than

D. None of these

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4

The bending moment M and a torque T is applied on a solid circular shaft. If the maximum bending stress equals to maximum shear stress developed, then M is equal to

A. T/2

B. T

C. 2T

D. 4T

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4

The centre distance between two meshing involute gears is equal to

A. (Sum of base circle radii)/cosφ

B. (Difference of base circle radii)/cosφ

C. (Sum of pitch circle radii)/cosφ

D. (Difference of pitch circle radii)/cosφ

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4

The coefficient of friction between the belt and pulley depends upon the

A. Material of belt and pulley

B. Slip of belt

C. Speed of belt

D. All of these

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4

The included angle for the British Association thread is

A. 29°

B. 55°

C. 47.3°

D. 60°

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4

Jam nut is a locking device in which

A. One smaller nut is tightened over main nut and main nut tightened against smaller one by loosening, creating friction jamming

B. A slot is cut partly in middle of nut and then slot reduced by tightening a screw

C. A hard fibre or nylon cotter is recessed in the nut and becomes threaded as the nut is screwed on the bolt causing a tight grip

D. Through slots are made at top and a cotter pin is passed through these and a hole in the bolt, and cotter spitted and bent in reverse direction at other end

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4

When a material is subjected to fatigue loading, the ratio of the endurance limit to the ultimate tensile strength is

A. 0.20

B. 0.35

C. 0.50

D. 0.65

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4

For same pulley diameters, center distance, belt speed and belt and pulley materials,

A. Open belt drive transmits more power than crossed belt drive

B. Crossed belt drive transmits more power than open belt drive

C. Open and crossed belt drives transmit same power

D. Power transmission does not depend upon open and crossed types of constructions

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4

A plate with an elliptical hole in the centre, with semi-major axis (A) perpendicular to the direction of loading and semi-minor axis (b) along the direction of loading, is subjected to a pull P. The maximum stress induced at the edge of the hole is equal to (where σ = Stress for a plate with no hole i.e. nominal stress)

A. σ [1 + (b/2a)]

B. σ [1 + (2a/b)]

C. σ [1 + (b/3a)]

D. σ [1 + (3a/b)]

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4

In helical gears, the right hand helixes on one gear will mesh __________ helixes on the other gear.

A. Right hand

B. Left hand

C. Both A and B

D. None of these

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4

The maximum efficiency of a square threaded screw is

A. (1 - sinφ)/ (1 + sinφ)

B. (1 + sinφ)/ (1 - sinφ)

C. (1 - sinφ)/ (1 + cosφ)

D. (1 + cosφ)/ (1 - sinφ)

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4

A coupling used to connect two perfectly aligned shafts, is

A. Muff coupling

B. Compression coupling

C. Flange coupling

D. All of these

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4

Rankine Gordon formula for buckling is valid for

A. Long column

B. Short column

C. Short and long column

D. Very long column

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4

The pitch of threads on a Jock nut in comparison to pitch of nut is

A. Same

B. Coarser

C. Finer

D. Very fine

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4

Stress concentration is caused due to

A. Variation in properties of material from point to point in a member

B. Pitting at points or areas at which loads on a member are applied

C. Abrupt change of section

D. All of the above

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4

A self locking screw has

A. Fine threads

B. Course threads

C. Coefficient of friction is greater than tangent of load angle

D. Hole for inserting split pin

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4

An open belt drive is used when

A. Shafts are arranged at right angles and rotate in one definite direction

B. Shafts are arranged parallel and rotate in the opposite directions

C. Shafts are arranged parallel and rotate in the same directions

D. Driven shaft is to be started or stopped whenever desired without interfering with the driving shaft

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4

According to I.B.R., when the thickness of boiler shell (t) is greater than 8 mm, then the diameter of rivet hole (d) is obtained by

A. Equating tearing resistance of the plate to the shearing resistance of the rivets

B. Equating tearing resistance of the plate to the crushing resistance of the rivets

C. Equating shearing resistance to the crushing resistance of the rivets

D. None of the above

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4

If the size of a standard specimen for a fatigue testing machine is increased, the endurance limit for the material will

A. Have same value as that of standard specimen

B. Increase

C. Decrease

D. None of these

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4

The minimum number of teeth on the pinion which will mesh with any gear without interference for 20° full depth involute teeth will be

A. 12

B. 14

C. 18

D. 24

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4

The temperature at which the new grains are formed in the metal is known as

A. Lower critical temperature

B. Upper critical temperature

C. Recrystallisation temperature

D. None of these

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4

A compound cylinder with inner radius 50 mm and outer radius 70 mm is made by shrinking one cylinder on to the other cylinder, the junction radius is 60 mm and the junction pressure is 1.1 N/mm². The maximum hoop stress developed in the inner cylinder is

A. 3.6 N/mm² compression

B. 3.6 N/mm² tension

C. 7.2 N/mm² compression

D. 7.2 N/mm² tension

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4

The load cup of a screw jack is made separate from the head of the spindle to

A. Prevent the rotation of load being lifted

B. Enhance the load carrying capacity of the jack

C. Reduce the effort needed for lifting the working load

D. Reduce the value of frictional torque

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4

Two shafts will have equal strength, if

A. Diameter of both the shafts is same

B. Angle of twist of both the shafts is same

C. Material of both the shafts is same

D. Twisting moment of both the shafts is same

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4

If a load W is applied instantaneously on a bar; Then the stress induced in bar will

A. Be independent of ratio of mass of load W to mass of bar (y)

B. Increase with increase in y

C. Decrease with decrease in y

D. Depend on other considerations