Description : Assertion (A): Hydrostatic lubrication is more advantageous when compared to hydrodynamic lubrication during starting and stopping the journal in its bearing. Reason (R): In hydrodynamic lubrication, the fluid film pressure is ... (c) A is true but R is false (d) A is false but R is true
Last Answer : (b) Both A and R are individually true but R is not the correct explanation of A
Description : The most suitable bearing for carrying very heavy loads with slow speed is (a) Hydrodynamic bearing (b) ball bearing [IAS 1994] (c) Roller bearing (d) hydrostatic bearing
Last Answer : (d) hydrostatic bearing
Description : Match List I with List II and select the : [IES-2002] List I (Bearings) List II (Load type) A. Hydrodynamic Journal bearing 1. High radial and thrust load combined B. Rectangular Hydrostatic bearing 2. Radial load only C. Taper Roller ... (a) 2 3 1 4 (b) 4 1 3 2 (c) 2 1 3 4 (d) 4 3 1 2
Last Answer : (a) 2 3 1 4
Description : Boundary lubricated bearing is (A) Thick film bearing (B) Thin film bearing (C) Hydrodynamic bearing (D) Hydrostatic bearing
Last Answer : (B) Thin film bearing
Description : Hydrostatic and hydrodynamic lubrication are the same thing. a) True b) False
Last Answer : b) False
Description : Partial bearing is preferred over journal bearing. a) True b) No c) More friction losses d) Can’t be determined
Last Answer : a) True
Description : Assertion (A): In steady rotating condition the journal inside a hydrodynamic journal bearing remains floating on the oil film. [IES-2008] Reason (R): The hydrodynamic pressure developed in steady rotating conditions in journal ... A (c) A is true but R is false (d) A is false but R is true
Last Answer : (a) Both A and R are true and R is the correct explanation of A
Description : When comes down to stress reduction, which one is preferred? a) Solid flywheel b) Split flywheel c) Both have equal stresses d) Cannot be determined
Last Answer : b) Split flywheel
Description : Satisfactory hydrodynamic film in a journal bearing is formed when (a) Journal speed is low; unit pressure on the bearing is high and viscosity of lubricant used is low [IES-2006] ... journal speed, unit pressure on bearing and lubricant viscosity exists resulting in low coefficient of friction
Last Answer : (c) Journal speed is high; unit pressure on the bearing is high and viscosity of lubricant used is high
Description : The bearing characteristic number in a hydrodynamic bearing depends on- (a) Length, width and load (b) length, width and speed. [IES-1996] (c) Viscosity, speed and load (d) viscosity, speed and bearing pressure.
Last Answer : (d) viscosity, speed and bearing pressure.
Description : What is the main advantage of hydrodynamic bearing over roller bearing? (a) Easy to assemble [IES-2005] (b) Relatively low price (c) Superior load carrying capacity at higher speeds (d) Less frictional resistance
Last Answer : (c) Superior load carrying capacity at higher speeds
Description : A journal bearing with hydrodynamic lubrication is running steadily with a certain amount of minimum film thickness. When the load and speed are doubled, how does the minimum film thickness vary? [IES-2008 ... Gets reduced to one-fourth of original value (d) Gets reduced to half of original value
Last Answer : (a) Remains unchanged
Description : Increase in values of which of the following results in an increase of the coefficient of friction in a hydrodynamic bearing? [IES 2007] 1. Viscosity of the oil. 2. Clearance between shaft and bearing. 3. Shaft speed. Select the ... 1 and 2 only (b) 1 and 3 only (c) 2 and 3 only (d) 1, 2 and 3
Last Answer : (b) 1 and 3 only
Description : Which one of the following is correct? [IES-2008] A hydrodynamic slider bearing develops load bearing capacity mainly because of- (a) Slider velocity (b) wedge shaped oil film (c) Oil compressibility (d) oil viscosity
Last Answer : (b) wedge shaped oil film
Description : In hydrodynamic bearing, (A) The axis of journal is eccentric with respect to axis of bearing (B) The axis of journal is concentric with respect to axis of bearing (C) The axis can be either eccentric or concentric depending upon speed (D) None of the above
Last Answer : (A) The axis of journal is eccentric with respect to axis of bearing
Description : For elasto-hydrodynamic lubrication (A) There should be relative motion between the surfaces of the journal and the bearing and wedge shaped clearance space (B) There should be external source like ... be elastic deformation of the parts in contact (D) There should be metal to metal contact
Last Answer : (C) There should be elastic deformation of the parts in contact
Description : For hydrodynamic lubrication (A) There should be relative motion between the surfaces of the journal and the bearing and wedge shaped clearance space (B) There should be external source like pump to ... be elastic deformation of the parts in contact (D) There should be metal to metal contact
Last Answer : (A) There should be relative motion between the surfaces of the journal and the bearing and wedge shaped clearance space
Description : In hydrodynamic bearing, when the shaft begins to rotate in clockwise direction, (A) The journal climbs to the right side of the bearing without metal to metal contact (B) The journal climbs to the left ... sinks down to the bottom of the bearing (D) The journal is at the center of the bearing
Last Answer : (A) The journal climbs to the right side of the bearing without metal to metal contact
Description : Sommerfeld number is (A) Similar to bearing characteristic number (B) Similar to Reynold’s number (C) Dimensionless parameter that contains all the design parameters (D) Used to find out dynamic load carrying capacity of the hydrodynamic bearing
Last Answer : (C) Dimensionless parameter that contains all the design parameters
Description : A journal bearing is a ______ contact bearing working on the hydrodynamic lubrication and which supports load in____ direction. a) Sliding, Axial b) Rolling, Radial c) Sliding, Radial d) Rolling, Axial
Last Answer : c) Sliding, Radial
Description : Hydrodynamic bearing is a self-acting bearing. a) True b) False
Description : For hydrostatic lubrication (A) There should be relative motion between the surfaces of the journal and the bearing and wedge shaped clearance space (B) There should be external source like pump to ... be elastic deformation of the parts in contact (D) There should be metal to metal contact
Last Answer : (B) There should be external source like pump to supply lubricant under pressure
Description : In hydrostatic bearing, (A) The axis of journal is eccentric with respect to axis of bearing (B) The axis of journal is concentric with respect to axis of bearing (C) The axis can be either eccentric or concentric depending upon speed (D) None of the above
Last Answer : (B) The axis of journal is concentric with respect to axis of bearing
Description : Which of the following bearing is preferred for oscillating conditions? (a) Double row roller bearing (b) Taper roller bearing (c) Needle roller bearing (d) Angular contact single row ball bearing
Last Answer : (c) Needle roller bearing
Description : A clearance bearing is design accurately to keep the radius of journal and bearing equal. a) Journal radius is kept larger b) Journal radius is kept smaller c) True d) Can’t be determined
Last Answer : b) Journal radius is kept smaller
Description : Assertion (A): In hydrodynamic journal bearings, the rotating journal is held in floating condition by the hydrodynamic pressure developed in the lubricant. Reason (R): Lubricant flows in a converging-diverging channel. [IES-1994] ... A (c) A is true but R is false (d) A is false but R is true
Last Answer : (a) Both A and R are individually true and R is the correct explanation of A
Description : Assertion (A): Oil as a cutting fluid result in a lower coefficient of friction. Reason (R): Oil forms a thin liquid film between the tool face and chip, and it provides 'hydrodynamic lubrication'. [IES- 2000] (a ... explanation of A (c) A is true but R is false (d) A is false but R is true
Last Answer : (c) A is true but R is false
Description : Assertion (A): In anti-friction bearings, the frictional resistance is very low as the shaft held by it remains in floating condition by the hydrodynamic pressure developed by the lubricant. [IES-2006] Reason (R): In hydrodynamic ... of A (c) A is true but R is false (d) A is false but R is true
Last Answer : (d) A is false but R is true
Description : How does the hydrostatic lubrication differ from hydrodynamic type?
Last Answer : In hydrostatic lubrication which is used in slow speed turbines the lubricating oil is pressurised externally where as in hydrodynamic system it forms oil film by its speed which pushes the lubrication oil to form film.
Description : The pressure that builds up in pore water due to load increment on the soil, is termed (A) Excess pore pressure (B) Excess hydrostatic pressure (C) Hydrodynamic pressure (D) All the above
Last Answer : Answer: Option D
Description : Starting friction is low in case of the __________ lubrication. (A) Boundary (B) Hydrodynamic (C) Hydrostatic (D) Mixed/semi-fluid
Last Answer : (C) Hydrostatic
Description : Antifriction bearings are (a) sleeve bearings (b) hydrodynamic bearings (c) thin lubricated bearings (d) none of the mentioned
Last Answer : (d) none of the mentioned
Description : Antifriction bearings are A. Sleeve bearings B. Hydrodynamic bearings C. Thin lubricated bearings D. None of the above
Last Answer : D. None of the above
Description : Which one of the following types of bearings is employed in shafts of gearboxes of automobiles? [IES-1999] (a) Hydrodynamic journal bearings (b) Multi-lobed journal bearings (c) Antifriction bearings (d) Hybrid journal bearings
Last Answer : (c) Antifriction bearings
Description : Which one of the following pair is correctly matched? [IES-2000] (a) Beauchamp tower ........................First experiments on journal bearings (b) Osborne Reynolds ........................ ... .Pivot and Collar bearings (d) Ball bearings...............................Hydrodynamic lubrication
Last Answer : (a) Beauchamp tower ........................First experiments on journal bearings
Description : In hydrodynamic lubrication, film thickness remains unaffected by change in speeds. a) True b) Increase with increase in speed c) Decrease with increase in speed d) Disappear as the speed tends to infinty
Last Answer : b) Increase with increase in speed
Description : In hydrostatic bearings (A) The Oil film pressure is generated only by the rotation of the journal (B) The oil film is maintained by supplying oil under pressure (C) Do not require external supply of lubricant (D) Grease is used for lubrication
Last Answer : (B) The oil film is maintained by supplying oil under pressure
Description : For a homogeneous & isotropic body under hydrostatic pressure, which theory of elastic failure does not fail (a) Firstly Maximum Principal Theory (b) Secondly Maximum Shear Stress Theory (c) Thirdly Maximum Principal Energy Theory (d) None
Last Answer : (a) Firstly Maximum Principal Theory
Description : For a homogeneous & isotropic body under hydrostatic pressure, which theory of elastic failure fails (a) Firstly Maximum Principal Theory (b) Secondly Maximum Principal strain Theory (c) Thirdly Maximum Principal Energy Theory (d) None
Last Answer : (c) Thirdly Maximum Principal Energy Theory
Description : In a body under hydrostatic pressure, the case exists (a) Firstly σ 1 > σ 2 =σ 3 (b) Secondly σ 1 = σ 2 =σ 3 (c) Thirdly σ 1 > σ 2 < σ 3 (d) None
Last Answer : (b) Secondly σ 1 = σ 2 =σ 3
Description : Which of the following cannot tolerate misalignment? (a) Angular contact bearing (b) Cylinder roller bearing (c) Thrust ball bearings (d) All of the listed
Last Answer : (d) All of the listed
Description : Which of the following cannot take the radial load? (a) Cylindrical Roller bearing (b) Taper roller bearing (c) Thrust ball bearing (d) Spherical roller bearing
Last Answer : (c) Thrust ball bearing
Description : Which of the following cannot tolerate misalignment? a) Angular contact bearing b) Cylinder roller bearing c) Thrust ball bearings d) All of the listed
Last Answer : d) All of the listed
Description : Which of the following cannot take radial load? a) Cylindrical Roller bearing b) Taper roller bearing c) Thrust ball bearing d) None of the listed
Last Answer : c) Thrust ball bearing
Description : If spring index=2.5, what can be concluded about stresses in the wire? a) They are high b) They are negligible c) They are moderate d) Cannot be determined
Last Answer : a) They are high
Description : Among gas and electric arc welding, which has the higher rate of heating? a) Gas welding b) Electric arc welding c) Gas welding and electric arc welding have equal rate of heating d) Cannot be determined
Last Answer : b) Electric arc welding
Description : Which threads have greater resistance to unscrewing? a) Coarse b) Fine c) They have equal resistance d) Cannot be determined
Last Answer : b) Fine
Description : Efficiency of the screw _______ with increase of coefficient of friction. a) decreases b) increases c) has no effect d) cannot be determined
Last Answer : a) decreases
Description : Use of multiple notches in a V shaped flat plate will a) Reduce the stress concentration b) Increase the stress concentration c) No effect d) Cannot be determined
Last Answer : a) Reduce the stress concentration
Description : For an elliptical hole on a flat plate, if width of the hole in direction of the load decrease, Stress Concentration Factor will______ a) Increase b) Decrease c) Remains constant d) Can’t be determined. Varies from material to material
Last Answer : a) Increase