The contact ratio for gears is
Zero
Less than one
Greater than one
None of these
Correct Answer :
C. Greater than one
Related Questions
In radial cams, the follower moves
In a direction parallel to the cam axis
In a direction perpendicular to the cam axis
In any direction irrespective of cam axis
Along the cam axis
Which of the following statement is correct?
The stress concentration in static loading is more serious in ductile materials and less serious in brittle materials
The stress concentration in static loading is more serious in brittle materials and less serious in ductile materials
The toughness of a material increases when it is heated
The shear stress in a beam varies from zero at the neutral surface and maximum at the outer fibres
Deep groove ball bearings are used for
Heavy thrust load only
Small angular displacement of shafts
Radial load at high speed
Combined thrust and radial loads at high speed
The square threads are usually found on
Spindles of bench vices
Railway carriage couplings
Feed mechanism of machine tools
Screw cutting lathes
The velocity of sliding ________ the distance of the point of contact from the pitch point.
Is directly proportional to
Is inversely proportional to
Is equal to cos φ multiplied by
Does not depend upon
A locking device in which the bottom cylindrical portion is recessed to receive the tip of the locking set screw, is called
Ring nut
Castle nut
Sawn nut
Jam nut
In testing a material for endurance strength, it is subjected to
Static load
Dynamic load
Impact load
Completely reversed load
The property of a bearing material which has the ability to accomodate shaft deflections and bearing inaccuracies by plastic deformation without excessive wear and heating, is known as
Bondability
Embeddability
Comformability
Fatigue strength
According to I.B.R., shearing resistance required to shear off the rivet per pitch length (in double shear) is (where n = Number of rivets per pitch length)
(π/4) d² × τ × n
1.875 × (π/4) d² × τ × n
2 × (π/4) d² × τ × n
3 × (π/4) d² × τ × n
The rated life of a bearing varies
Directly as load
Inversely as square of load
Inversely as cube of load
Inversely as fourth power of load
When the fulcrum is in between the load and effort, the lever is said to be of
First type
Second type
Third type
Any one of these
Stress concentration in static loading is more serious in
Ductile materials
Brittle materials
Equally serious in both cases
Depends on other factors
During hot working of metals,
Porosity of the metal is largely eliminated
Grain structure of the metal is refined
Mechanical properties are improved due of refinement of grains
All of the above
The stress which vary from a minimum value to a maximum value of the same nature (i.e. tensile or compressive) is called
Repeated stress
Yield stress
Fluctuating stress
Alternating stress
Stress concentration factor is defined as the ratio of
Maximum stress to the endurance limit
Nominal stress to the endurance limit
Maximum stress to the nominal stress
Nominal stress to the maximum stress
When spring index increases, the value of Wahl's stress factor
Increases linearly
Decreases linearly
Remains same
Increases exponentially
At low temperatures (say 75°C) the notched bar impact value of steel
Increases markedly
Decreases markedly
Remain same
Depends on heat treatment carried out
In worm gears, the angle between the tangent to the pitch helix and an element of the cylinder, is known as
Helix angle
Pressure angle
Pitch lead angle
None of these
The gears are termed as medium velocity gears, if their peripheral velocity is
1-3 m/s
3-15 m/s
15-30 m/s
30-50 m/s
The initial tension (in newtons) in a bolt used for making a fluid tight joint like steam engine cover joints, is calculated by the relation (where d = Nominal diameter of bolt in mm)
1420 d
1680 d
2080 d
2840 d
The coefficient of friction in belt drive depends upon
Material of belt
Material of pulley
Materials of belt and pulley
Belt velocity
The power transmitted by the belt drive can be increased by
Increasing the initial tension in the belt
Dressing the belt to increase the coefficient of friction
Increasing wrap angle by using idler pulley
All of the above methods
In order to avoid tearing of the plate at edge, the distance from the center line of the rivet hole to the nearest edge of the plate in terms of dia. of rivet d should be equal to
d
1.25 d
1.5 d
1.75 d
Which of the following material has the maximum ductility?
Copper
Mild steel
Aluminium
Zinc
In order to avoid tearing of the plate at an edge, the distance from the centre line of the rivet hole to the nearest edge of the plate should be equal to (where d = Diameter of rivet hole)
d
1.5 d
2.5 d
2 d
Endurance limit or fatigue limit is the maximum stress that a member can withstand for an infinite number of load applications without failure when subjected to
Dynamic loading
Static loading
Combined static and dynamic loading
Completely reversed loading
The property of a material which enables it to resist fracture due to high impact loads is known as
Elasticity
Endurance
Strength
Toughness
The design calculations for members subject to fluctuating loads with the same factor of safety, yield the most conservative estimates when using
Gerber relation
Soderberg relation
Goodman relation
None of these
A key made from a cylindrical disc having segmental cross-section, is known as
Woodruff key
Feather key
Flat saddle key
Gib head key
The pipe joint mostly used for pipes carrying water at low pressures is
Socket joint
Nipple joint
Union joint
Spigot and socket joint