A sliding bearing in which although lubricant is present, the working surfaces __________ contact each other at least part of the time, is called boundary lubricated bearing.
Partially
Fully
Either A or B
None of these
Correct Answer :
A. Partially
Related Questions
Which of the following statement is wrong for a connecting rod?
The connecting rod will be equally strong in buckling about X-axis and Y-axis, if Ixx = 4 Iyy
If Ixx > 4 Iyy, the buckling will occur about Y-axis
If Ixx < 4 Iyy, the buckling will occur about X-axis
The most suitable section for the connecting rod is T-section
In the case of an elastic bar fixed at upper end and loaded by a falling weight at lower end, the shock load produced can be decreased by
Decreasing the cross-section area of bar
Increasing the cross-section area of bar
Remain unaffected with cross-section area
Would depend upon other factors
A tapered key which fits in a key-way in the hub and is flat on the shaft, is known as
Woodruff key
Feather key
Flat saddle key
Gib head key
The strap end of a connecting rod of steam engine is joined by
Gib of cotter joint
Sleeve and cotter joint
Spigot socket cotter joint
Knuckle joint
Machine 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 two parts
Similar to stud
A bench vice has following type of threads
Metric
Square
Buttress
Acme
Basic shaft is one
Whose upper deviation is zero
Whose lower deviation is zero
Whose lower as well as upper deviations are zero
Does not exist
The cross-section of the arm of a bell crank lever is
Rectangular
Elliptical
I-section
Any one of these
A tapered key which fits in a key way in the hub and the bottom of which is shaped to fit the curved surface of the shaft, is known as,
Hollow saddle key
Hollow key
Soft key
None of these
In cylindrical cams, the follower moves
In a direction perpendicular to the cam axis
In a direction parallel to the cam axis
In any direction irrespective of cam axis
Along the cam axis
A fast and loose pulley drive is used when
Shafts are arranged parallel and rotate in the opposite directions
Shafts are arranged parallel and rotate in the same directions
Shafts are arranged at right angles and rotate in one definite direction
Driven shaft is to be started or stopped whenever desired without interfering with the driving shaft
In a hydrodynamic lubricated bearing
There is a thick film of lubricant between the journal and the bearing
There is a thin film of lubricant between the journal and the bearing
The lubricant is forced between the journal and the bearing, by external pressure
There is no lubricant between the journal and the bearing
Which is correct statement? Stress concentration in cyclic loading is
Very serious in brittle materials and less serious in ductile materials
Very serious in ductile materials and less serious in brittle materials
Equally serious in both types of materials
Seriousness would depend on other factors
If the centre distance of the mating gears having involute teeth is increased, then the pressure angle
Increases
Decreases
Remains unchanged
None of these
Wahl's stress factor __________ very rapidly as the spring index decreases.
Increases
Decreases
Remain same
None of these
Fabric belts are used in industrial applications because
They are cheap
They can work at high temperature
They are unaffected by moisture and humidity
None of the above
Which one of the following loading is considered for the design of axles?
Bending moment only
Twisting moment only
Combined bending moment and twisting moments
Combined action of bending moment, twisting moment and axial thrust
The material commonly used for crane hooks is
Cast iron
Wrought iron
Mild steel
Aluminium
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
Angular bevel gears
Mitre gears
Internal bevel gears
Crown bevel gears
The usual clearance provided in hydrodynamic bearing per mm of diameter of shaft is
0.01 micron
0.1 micron
1 micron
10 microns
In a multiple V-belt drive, when a single belt is damaged, it is preferable to change the complete set in order to
Reduce vibration
Reduce slip
Ensure uniform loading
Ensure proper alignment
The shock resistance of steel is increased by adding
Nickel
Chromium
Nickel and chromium
Cobalt and molybdenum
The ratio of driving tensions in V-belt drives is __________ flat belt drives.
Equal to
sinα times more than
sinα times less than
cosecα times more than
A tube has the following advantage over pipe
Lighter and easier to handle
Greater shock absorption
Smoother inside walls
All of the above
An imaginary circle which by pure rolling action gives the same motion as the actual gear, is called
Addendum circle
Dedendum circle
Pitch circle
Clearance circle
The efficiency of a riveted joint is equal to
Pt /P
Ps /P
Pc /P
Least of Pt, Ps and Pc/P
Which of the following statement is correct for gears?
The pitch circle diameter is equal to the product of module and number of teeth
The addendum is less than dedendum
The pitch circle is always greater than the base circle
All of the above
A locking device extensively used in marine type connecting rod ends is a
Jam nut
Castle nut
Sawn nut
Ring nut
The rolling contact bearings as compared to sliding contact bearings have
Low starting and low running friction except at very high speeds
Accuracy of shaft alignment
Small overall dimensions
All of the above
In standard taper roller bearings, the angle of taper of outer raceway is
5°
8°
15°
25°