Limiting Angle of Friction

Question 1
Marks : +2 | -2
Pass Ratio : 100%
When the two solid surfaces sliding over each other are free from contaminating fluid or film, the resistance encountered is called
kinetic friction
dry friction
boundary lubrication
none of the mentioned
Explanation:
When the two solid surfaces sliding over each other are free from contaminating fluid or film, the resistance encountered is called dry friction.
Question 2
Marks : +2 | -2
Pass Ratio : 100%
When the rubbing surfaces are separated from each other by a very thin film of lubricant it is known as
kinetic friction
dry friction
boundary lubrication
none of the mentioned
Explanation:
When the rubbing surfaces are separated from each other by a very thin film of lubricant it is known as boundary lubrication.
Question 3
Marks : +2 | -2
Pass Ratio : 100%
For design of ordinary machinery, value of journal friction can be taken as
0.008 to 0.02
0.07 to 0.15
0.05 to 0.80
none of the mentioned
Explanation:
For very low velocities of rotation, high loads, and with good lubrication can be taken as 0.07 to 0.15.
Question 4
Marks : +2 | -2
Pass Ratio : 100%
When the lubrication is arranged so that rubbing surfaces are separated by a fluid film, and the load on the surfaces is carried entirely by the hydrostatic or hydrodynamic pressure in the film, it is known as
boundary lubrication
viscous lubrication
solid lubrication
none of the mentioned
Explanation:
When the lubrication is arranged so that rubbing surfaces are separated by a fluid film, and the load on the surfaces is carried entirely by the hydrostatic or hydrodynamic pressure in the film, it is known as viscous lubrication.
Question 5
Marks : +2 | -2
Pass Ratio : 100%
When effect of friction is negligible, the force is transmitted by the link from driver to the driven link through the centre line of the pins connecting the link. With friction, the line of action shifts and is tangent to _____________
kinetic friction
dry friction
friction circle
none of the mentioned
Explanation:
When effect of friction is negligible, the force is transmitted by the link from driver to the driven link through the centre line of the pins connecting the link. With friction, the line of action shifts and is tangent to friction circle.
Question 6
Marks : +2 | -2
Pass Ratio : 100%
__________ is used to resist the end thrust of the shafts.
friction circle
step bearings
injector
none of the mentioned
Explanation:
Step bearing is used to resist the end thrust of the shafts.
Question 7
Marks : +2 | -2
Pass Ratio : 100%
If one surface slides over the other, being pressed together by a normal force N, a frictional force F resisting the motion must be overcome. The ratio F/N is called ______________
kinetic friction
dry friction
friction circle
none of the mentioned
Explanation:
If one surface slides over the other, being pressed together by a normal force N, a frictional force F resisting the motion must be overcome. The ratio F/N is called kinetic friction.
Question 8
Marks : +2 | -2
Pass Ratio : 100%
When the load on the rubbing surfaces is carried partly by a fluid viscous film and partly by areas of boundary lubrication, it is known as
incomplete lubrication
viscous lubrication
solid lubrication
none of the mentioned
Explanation:
When the lubrication is arranged so that rubbing surfaces are separated by a fluid film, and the load on the surfaces is carried entirely by the hydrostatic or hydrodynamic pressure in the film, it is known as viscous lubrication.
Question 9
Marks : +2 | -2
Pass Ratio : 100%
For very low velocities of rotation, high loads, and with good lubrication can be taken as
0.008 to 0.02
0.07 to 0.15
0.05 to 0.80
none of the mentioned
Explanation:
For very low velocities of rotation, high loads, and with good lubrication can be taken as 0.07 to 0.15.
Question 10
Marks : +2 | -2
Pass Ratio : 100%
Sliver sulphate, tungsten disulphide, graphite, molybdenum disulphide, lead oxide are examples of
boundary lubrication
viscous lubrication
solid lubrication
none of the mentioned
Explanation:
Sliver sulphate, tungsten disulphide, graphite, molybdenum disulphide, lead oxide are examples of solid lubrication.