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4

In hydrodynamic bearings

A. The oil film pressure is generated only by the rotation of the journal

B. The oil film is maintained by supplying oil under pressure

C. Do not require external supply of lubricant

D. Grease is used for lubrication

Correct Answer :

A. The oil film pressure is generated only by the rotation of the journal


Related Questions

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4

According to I.B.R., the efficiency of a double riveted butt joint with double cover straps of equal width should be

A. 45 to 60 %

B. 63 to 70 %

C. 70 to 83 %

D. 80 to 90 %

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4

The material commonly used for machine tool bodies is

A. Mild steel

B. Aluminium

C. Brass

D. Cast iron

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4

A thin spherical shell of internal diameter d is subjected to an internal pressure p. If V is the storage capacity of shell, then its diameter will be

A. (6V/ π)1/2

B. (6V/ π)1/3

C. (6V/ π)2

D. (6V/ π)3

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4

The bending stress in a curved beam is

A. Zero at the centroidal axis

B. Zero at the point other than centroidal axis

C. Maximum at the neutral axis

D. None of these

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4

When an open coiled helical compression spring is subjected to an axial load (W), the compression produced in the spring will be (where n = No. of active turns of the spring, and G = Modulus of rigidity for the spring material)

A. 2WD3n/Gd⁴

B. 4WD3n/Gd⁴

C. 8WD3n/Gd⁴

D. 16WD3n/Gd⁴

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4

If threads on a bolt are left hand, threads on nut will be

A. Right hand with same pitch

B. Left hand with same pitch

C. Could be left or right hand

D. Right hand with fine pitch

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4

The modulus of elasticity for mild steel is approximately equal to

A. 80 kN/mm²

B. 100 kN/mm²

C. 110 kN/mm²

D. 210 kN/mm²

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4

The fatigue life of a part can be improved by

A. Electroplating

B. Polishing

C. Coating

D. Shot peening

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4

The material commonly used for crane hooks is

A. Cast iron

B. Wrought iron

C. Mild steel

D. Aluminium

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4

The allowable static stress for steel gears is approximately __________ of the ultimate tensile stress.

A. One-fourth

B. One-third

C. One-half

D. Double

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4

A sliding bearing which can support steady loads without any relative motion between the journal and the bearing, is called

A. Hydrostatic lubricated bearing

B. Hydrodynamic lubricated bearing

C. Boundary lubricated bearing

D. Zero film bearing

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4

The resilience of a bolt may be increased by

A. Increasing its shank diameter

B. Increasing its length

C. Decreasing its shank diameter

D. Decreasing its length

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4

For a shoe brake, the equivalent coefficient of friction is equal to (where μ = Actual coefficient of friction, and θ = Semi-block angle)

A. 2μ sinθ/(θ + sinθ)

B. μ sinθ/(2θ + sin 2θ)

C. 4μ sinθ/(θ + sinθ)

D. 4μ sinθ/(2θ + sin 2θ)

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4

Which of the following statement is correct, for two shafts connected in parallel?

A. Torque in each shaft is the same

B. Shear stress in each shaft is the same

C. Angle of twist of each shaft is the same

D. Torsional stiffness of each shaft is the same

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4

A bolt is designed on the basis of __________ with a large factor of safety.

A. Direct tensile stress

B. Direct compressive stress

C. Direct bending stress

D. Direct shear stress

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4

Which is correct statement? Stress concentration in static loading is

A. Very serious in brittle materials and less serious in ductile materials

B. Very serious in ductile materials and less serious in brittle materials

C. Equally serious in both types of materials

D. Seriousness would depend on other factors

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4

The dedendum circle diameter is equal to (where φ = Pressure angle)

A. Pitch circle diameter × cosφ

B. Addendum circle diameter × cosφ

C. Clearance circle diameter × cosφ

D. Pitch circle diameter × sinφ

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4

Coaxing is the procedure of increasing

A. Metal strength by cycling

B. Metal hardness by surface treatment

C. Metal resistance to corrosion by coating

D. Fatigue limit by overstressing the metal by successively increasing loadings

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4

In radial cams, the follower moves

A. In a direction parallel to the cam axis

B. In a direction perpendicular to the cam axis

C. In any direction irrespective of cam axis

D. Along the cam axis

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4

In designing thick cylinders, the equation used is

A. Lame's equation

B. Birnie's equation

C. Clavarinos' equation

D. All of these

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4

Spring stiffness is

A. Ratio of coil diameter to wire diameter

B. Load required to produce unit deflection

C. Its capability of storing energy

D. Its ability to absorb shocks

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4

The material used for brake lining should have __________ coefficient of friction.

A. Low

B. High

C. Moderate

D. None of these

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4

The number of slots in a 25 mm castle nut is

A. 8

B. 4

C. 2

D. 6

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4

A fast and loose pulley drive is used when

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

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

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

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

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4

Two closely coiled helical springs with stiffness k₁ and k₂ respectively are connected in series. The stiffness of an equivalent spring is given by

A. (k₁ k₂)/ (k₁ + k₂)

B. (k₁ - k₂)/ (k₁ + k₂)

C. (k₁ + k₂)/ (k₁ k₂)

D. (k₁ - k₂)/ (k₁ k₂)

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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

A spring is used to

A. Measure forces

B. Apply forces

C. Store energy

D. All of these

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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

In the levers of first type, the mechanical advantage is __________ one.

A. Less than

B. Equal to

C. More than

D. None of these

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4

The width of the pulley should be __________ width of the belt.

A. Equal to

B. Less than

C. Greater than

D. None of these