A localised compressive stress at the area of contact between two members is known as
Bending stress
Shear stress
Tensile stress
Bearing stress
Correct Answer :
D. Bearing stress
Related Questions
The square threads are usually found on
Spindles of bench vices
Railway carriage couplings
Feed mechanism of machine tools
Screw cutting lathes
In helical gears, the distance parallel to the axis, between similar faces of adjacent teeth, is called
Normal pitch
Axial pitch
Diametral pitch
Module
While designing a screw in a screw jack against buckling failure, the end conditions for the screw are taken as
Both the ends fixed
Both the ends hinged
One end fixed and the other end hinged
One end fixed and the other end free
Creep in belt is due to
Material of the belt
Material of the pulley
Uneven extensions and contractions due to varying tension
All of the above
If p = bearing pressure on projected bearing area, z = absolute viscosity of lubricant, and N = speed of journal, then the bearing characteristic number is given by
ZN/p
p/ZN
Z/pN
N/Zp
Yield point in fatigue loading as compared to static loading is
Same
Higher
Lower
Depends on other factors
A localised compressive stress at the area of contact between two members is known as
Tensile stress
Bending stress
Bearing stress
Shear stress
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
When a close coiled helical spring is compressed, its wire is subjected to
Tension
Shear
Compression
All of the above
The form factor of a helical gear __________ with the increase in the helix angle.
Increases
Decreases
Remains constant
None of these
Cap screws are
Similar to small size tap bolts except that a greater variety of shapes of heads are available
Slotted for a screw driver and generally used with a nut
Used to prevent relative motion between parts
Provided with detachable caps
The ratio of endurance limit in shear to the endurance limit in flexure is
0.33
0.4
0.5
0.55
The temperature required for full annealing in hypereutectoid steel is
50°C above upper critical temperature
50°C below upper critical temperature
50°C above lower critical temperature
50°C below lower critical temperature
Plastic flow in ductile materials
Increases the seriousness of static loading stress concentration
Lessens the seriousness of static loading stress concentration
Has no effect on it
Depends on other considerations
The washer is generally specified by its
Outer diameter
Hole diameter
Thickness
Mean diameter
The creep in the belt is due to
Effect of temperature on belt
Material of belt
Unequal extensions in the belt due to tight and slack side tensions
Stresses beyond elastic limit of belt material
The toughness of a material _________ when it is heated
Does not change
Increases
Decreases
None of the Above
Screws used for power transmission should have
Very fine threads
High efficiency
Low efficiency
Strong teeth
If P1 and P2 are the tight and slack side tensions in the belt, then the initial tension Pi (according to Barth) will be equal to
[(√P1 + √P2)/2]²
P1 + P2
2 × (P1 + P2)
[2 × (P1 + P2)] + Pc Where Pc is centrifugal tension
The centrifugal tension in belts
Decreases the power transmitted
Increases the power transmitted
Increase the wrap angle
Increases the belt tension without increasing power transmission
For unequal width of butt straps, the thicknesses of butt straps are
0.75 t for narrow strap on the inside and 0.625 t for wide strap on the outside
0.75 t for wide strap on the inside and 0.625 t for narrow strap on the outside
0.75 t for both the straps on the inside and outside
0.625 t for both the straps on the inside and outside
In helical gears, the right hand helixes on one gear will mesh __________ helixes on the other gear.
Right hand
Left hand
Both A and B
None of these
A circular shaft can transmit a torque of 5 kN-m. If the torque is reduced to 4 kN-m, then the maximum value of bending moment that can be applied to the shaft is
1 kN-m
2 kN-m
3 kN-m
4 kN-m
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
A steel containing 0.8% carbon is known as
Eutectoid steel
Hypereutectoid steel
Hypo-eutectoid steel
None of these
When screw threads are to be used in a situation where power is being transmitted in one direction only, then the screw threads suitable for this will be
Knuckle threads
Square threads
Acme threads
Buttress threads
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)
σ [1 + (b/2a)]
σ [1 + (2a/b)]
σ [1 + (b/3a)]
σ [1 + (3a/b)]
Elastic nut is a locking device in which
One small nut is tightened over main nut and main nut tightened against smaller one by loosening, creating friction jamming
A slot is cut partly in middle of nut and then slot reduced by tightening a screw
Hard fibre or nylon cotter is recessed in the nut and becomes threaded as the nut is stewed on the bolt causing a tight grip
Through slots are made at top and a cotter pin is passed through these and a hole in the bolt, and cotter pin splitted and bent in reverse direction at other end
The power transmitted by belt drive depends upon
Belt velocity
Initial belt tension
Arc of contact
All of the above
Three different weights fall from a certain height under vacuum. They will take
Same time to reach earth
Times proportional to weight to reach earth
Times inversely proportional to weight to reach earth
None of the above