When the bearing is subjected to large fluctuations of load and heavy impacts, the bearing characteristic number should be _________ the bearing modulus.
10 times
5 times
15 times
20 times
Correct Answer :
C. 15 times
Related Questions
Applications in which stresses are encountered in one direction only uses following type of threads
Metric
Buttress
Acme
Square
A key made from a cylindrical disc having segmental cross-section, is known as
Woodruff key
Feather key
Flat saddle key
Gib head key
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
(6V/ π)1/2
(6V/ π)1/3
(6V/ π)2
(6V/ π)3
In an oil lubricated journal bearing, the coefficient of friction between the journal and the bearing
Remains constant at all speeds
Is minimum at zero speed and increases monotonically with increase in speed
Is maximum at zero speed and decreases monotonically with increase in speed
Becomes minimum at an optimum speed and then increases with further increase in speed
The cold working of metals is carried out __________ the recrystallisation temperature.
Above
Below
At
None of these
The width of the pulley should be __________ width of the belt.
Equal to
Less than
Greater than
None of these
The draw of cotter need not exceed
3 mm
5 mm
10 mm
20 mm
A shaft is subjected to a maximum bending stress of 80 N/mm² and maximum shearing stress equal to 30 N/mm² at a particular section. If the yield point in tension of the material is 280 N/mm² and the maximum shear stress theory of failure is used, then the factor of safety obtained will be
2.5
2.8
3.0
3.5
Residual stress in materials
Acts when external load is applied
Becomes zero when external load is removed
Is independent of external loads
Is always harmful
The centre distance between two meshing involute gears is equal to
(Sum of base circle radii)/cosφ
(Difference of base circle radii)/cosφ
(Sum of pitch circle radii)/cosφ
(Difference of pitch circle radii)/cosφ
Whether any core is required in wire ropes
Yes
No
Sometimes
Rarely
When a material is subjected to fatigue loading, the ratio of the endurance limit to the ultimate tensile strength is
0.20
0.35
0.50
0.65
When bevel gears connect two shafts whose axes intersect at an angle greater than a right angle and one of the bevel gears has a pitch angle of 90°, then they are known as
Crown bevel gears
Angular bevel gears
Mitre gears
Internal bevel gears
Fibrous fracture occurs in
Ductile material
Brittle material
Elastic material
Hard material
The suitable material for belt used in flour mill is
Leather
Rubber
Canvas or cotton duck
Balata gum
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
When two non-parallel or intersecting but coplanar shafts are connected by gears, the arrangement is known as,
Bevel gearing
Helical gearing
Worm gearing
None of these
When the shaft rotates in anticlockwise direction at slow speed in a bearing, it will
Have contact at the bottom most of the bearing
Move towards right of the bearing making no metal to metal contact
Move towards right of the bearing making the metal to metal contact
Move towards left of the bearing making metal to metal contact
The size of a cam depends upon
Base circle
Pitch circle
Prime circle
Pitch curve
Two shafts will have equal strength, if
Diameter of both the shafts is same
Angle of twist of both the shafts is same
Material of both the shafts is same
Twisting moment of both the shafts is same
In a flange coupling, the flanges are coupled together by means of
Bolts and nuts
Studs
Headless taper bolts
None of these
In order to obtain bolt of uniform strength
Increase shank diameter
Increase its length
Drill an axial hole through head up to threaded portion so that shank area is equal to root area of thread
Tighten die bolt properly
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
Jam nut is a locking device in which
One smaller 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
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
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
A tap bolt
Has a head on one end and a nut fitted to the other
Has head at one end and other end fits into a tapped hole in the other part to be joined
Has both the ends threaded
Has pointed threads
An open belt drive is used when
Shafts are arranged at right angles and rotate in one definite direction
Shafts are arranged parallel and rotate in the opposite directions
Shafts are arranged parallel and rotate in the same directions
Driven shaft is to be started or stopped whenever desired without interfering with the driving shaft
The value of stress concentration factor depends upon
Material and geometry of the part
Geometry of the part
Material of the part
None of these
The deflection of a cantilever beam under load W is 8. If its width is halved, then the deflection under load W will be
2/8
8/2
4/8
8/4
A screw is said to be a self locking screw, if its efficiency is
Less than 50 %
More than 50 %
Equal to 50 %
None of these
The expansion joint is mostly used for pipes which carry steam at __________ pressures.
Low
High
Medium
None of these