A localized compressive stress at the area of contact between two members is known as
1.Bending stress
2.Shear stress
3.Tensile stress
4. Bearing stress
According to I.B.R., when the thickness of boiler shell (t) is greater than 8 mm, then the diameter of rivet hole (d) is obtained by
1.Equating tearing resistance of the plate to the shearing resistance of the rivets
2. Equating tearing resistance of the plate to the crushing resistance of the rivets
3. Equating shearing resistance to the crushing resistance of the rivets
4.None of the above
Antifriction bearings are
1.Sleeve bearings
2.Hydrodynamic bearings
3.Thin lubricated bearings
4.None of the above
For hardening alloy steels and high speed steels, they are heated to
1.1100 to 1300°C
2. 1300 to 1500°C
3. 500 to 600°C
4.700 to 900°C
For same pulley diameters, center distance, belt speed and belt and pulley materials,
1. Open belt drive transmits more power than crossed belt drive
2.Crossed belt drive transmits more power than open belt drive
3.Open and crossed belt drives transmit same power
4.Power transmission does not depend upon open and crossed types of constructions
I.S. specifies following total number of grades of tolerances
1. 18
2.16
3.20
4.22
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
1. ZN/p
2.p/ZN
3.Z/pN
4.N/Zp
If shearing stress in nut is half the tensile stress in a bolt, then nut length should be equal to
1.Diameter of bolt
2.0.75 × diameter of bolt
3.1.25 × diameter of bolt
4.1.5 × diameter of bolt
In case of V belt drive
1. The belt should touch the bottom of groove in the pulley
2.The belt should not touch the bottom of groove in the pulley
3.The belt should not touch the sides of groove in the pulley
4.None of the above
In leaf springs, the longest leaf is known as
1.Master leaf
2.Lower leaf
3.Upper leaf
4.None of these
Oil in journal bearing should be applied at the point where load is
1.Nil or lightest
2. Maximum
3.Average
4.Any one of the above
Screws used for power transmission should have
1. Low efficiency
2. High efficiency
3.Very fine threads
4.Strong teeth
Stress concentration in static loading is more serious in
1. Ductile materials
2. Brittle materials
3.Equally serious in both cases
4.Depends on other factors
The application of third type levers is found in
1.Handle of a hand pump
2.Hand wheel of a punching press
3. Lever of a loaded safety valve
4.A pair of tongs
The edges of the plates for cylindrical vessels are usually bevelled to an angle of 80° for
1.Reducing stress concentration
2.Ease of manufacture
3.Safety
4.Fullering and caulking
The maximum stress due to stress concentration in a bar having circular transverse hole, as compared to its static stress without hole will be
1.Same in both cases
2. 2 times more
3. 3 times more
4. 4 times more
The metal suitable for bearings subjected to heavy loads is
1.White metal
2.Silicon bronze
3.Monel metal
4.Phosphor bronze
The objective of ‘crowning’ of the flat pulleys of belt drive is to
1.Prevent the belt from running off the pulley
2.Increase the power transmission capacity
3. Increase the belt velocity
4. Prevent the belt joint from damaging the belt surface
The objective of ‘crowning’ of the flat pulleys of belt drive is to
1.Prevent the belt from running off the pulley
2.Increase the power transmission capacity
3.Increase the belt velocity
4.Prevent the belt joint from damaging the belt surface
The pipe joint mostly used for pipes carrying water at low pressures is
1.Socket joint
2.Nipple joint
3.Union joint
4.Spigot and socket joint
The shearing stresses in the inner face as compared to outer face of the wire in a heavy close coiled spring is
1.Larger
2.Smaller
3.Equal
4.Larger/smaller depending on diameter of spring coil
When two springs are in series (having stiffness K), the equivalent stiffness will be
1. K
2.K/2
3.2K
4. K/4
Whether any core is required in wire ropes
1. Yes
2.No
3.Sometimes
4.Rarely
Which is correct statement? Stress concentration in cyclic loading is
1.Very serious in brittle materials and less serious in ductile materials
2.Very serious in ductile materials and less serious in brittle materials
3.Equally serious in both types of materials
4.Seriousness would depend on other factors
A bolt of uniform strength can be developed by
1.Keeping the core diameter of threads equal to the diameter of unthreaded portion of the bolt
2.Keeping the core diameter smaller than the diameter of the unthreaded portion
3.Keeping the nominal diameter of threads equal to the diameter of unthreaded portion of the bolt
4.None of the above
A bolt of uniform strength can be developed by
1.Keeping the core diameter of threads equal to the diameter of unthreaded portion of the bolt
2.Keeping the core diameter smaller than the diameter of the unthreaded portion
3.Keeping the nominal diameter of threads equal to the diameter of unthreaded portion of the bolt
4.None of the above
A localized compressive stress at the area of contact between two members is known as
1.Bending stress
2.Shear stress
3.Tensile stress
4. Bearing stress
A screw is said to be over hauling screw, if its efficiency is
1.More than 50%
2.Less than 50%
3.Equal to 50%
4.None of these
A sliding bearing which operates without any lubricant present, is called
1. Zero film bearing
2.Boundary lubricated bearing
3.Hydrodynamic lubricated bearing
4. Hydrostatic lubricated bearing
A universal coupling is used to connect two shafts
1.Which are not in exact alignment
2.Which are perfectly aligned
3.Whose axes intersect at a small angle
4.Have lateral misalignment
An open belt drive is used when
1.Shafts are arranged at right angles and rotate in one definite direction
2.Shafts are arranged parallel and rotate in the opposite directions
3.Shafts are arranged parallel and rotate in the same directions
4.Driven shaft is to be started or stopped whenever desired without interfering with the driving shaft
Basic hole is one
1.Whose upper deviation is zero
2.Whose lower deviation is zero
3. Whose lower as well as upper deviations are zero
4.Does not exist
Basic shaft is one
1.Whose upper deviation is zero
2.Whose lower deviation is zero
3.Whose lower as well as upper deviations are zero
4. Does not exist
Euler’s formula for a mild steel column is not valid if the slenderness ratio is
1.90
2.60
3.100
4.120
Form coefficient of spring is
1.Ratio of coil diameter to wire diameter
2.Load required to produce unit deflection
3.Its capability of storing energy
4.Concerned with strength of wire of spring
If a bearing is designated by the number 305, it means that the bearing is of
1.Medium series whose bore is 5 mm
2. Medium series whose bore is 25 mm
3.Light series whose bore is 25 mm
4.Light series whose bore is 5 mm
If a material fails below its yield point, failure would be due to
1.Straining
2.Fatigue
3.Creep
4.Sudden loading
If two springs are in parallel then their overall stiffness will be
1.Half
2.Same
3.Double
4.All of the above
In composite or reverse laid ropes
1.Direction of twist of wires in strands is opposite to the direction of twist of strands
2. Direction of twist of wires and strands are same
3.Wires in two adjacent strands are twisted in opposite direction
4.Wires are not twisted
In cross or regular lay ropes
1. Direction of twist of wires in strands is opposite to the direction of twist of strands
2.Direction of twist of wires and strands are same
3.Wires in two adjacent strands are twisted in opposite direction
4.Wires are not twisted
In hydrodynamic bearings
1.The oil film pressure is generated only by the rotation of the journal
2. The oil film is maintained by supplying oil under pressure
3.Do not require external supply of lubricant
4.Grease is used for lubrication
In hydrostatic bearings
1.The Oil film pressure is generated only by the rotation of the journal
2.The oil film is maintained by supplying oil under pressure
3.Do not require external supply of lubricant
4.Grease is used for lubrication
In standard taper roller bearings, the angle of taper of outer raceway is
1.5°
2.8°
3.15°
4. 25°
In testing a material for endurance strength, it is subjected to
1. Static load
2.Dynamic load
3.Impact load
4.Completely reversed load
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
1.Decreasing the cross-section area of bar
2. Increasing the cross-section area of bar
3.Remain unaffected with cross-section area
4.Would depend upon other factors
Maximum principal stress theory is applicable for
1. Ductile materials
2.Brittle materials
3.Elastic materials
4.All of the above
Maximum principal stress theory is applicable for
1.Ductile materials
2.Brittle materials
3. Elastic materials
4.All of the above
Maximum principal stress theory is applicable for
1.Ductile materials
2.Brittle materials
3. Elastic materials
4.All of the above
Resistance to fatigue of a material is measured by
1.Young's modulus
2. Coefficient of elasticity
3.Elastic limit
4.Endurance limit
Spring index is
1. Ratio of coil diameter to wire diameter
2. Load required to produce unit deflection
3.Its capability of storing energy
4.Indication of quality of spring
Spring stiffness is
1.Ratio of coil diameter to wire diameter
2.Load required to produce unit deflection
3.Its capability of storing energy
4. Its ability to absorb shocks
The bearings of heavy series have capacity __________ over the medium series.
1.20 to 30%
2.10 to 20%
3.30 to 40%
4. 40 to 50%
The creep in the belt is due to
1. Effect of temperature on belt
2.Material of belt
3.Unequal extensions in the belt due to tight and slack side tensions
4.Stresses beyond elastic limit of belt material
The crest diameter of a screw thread is same as
1.Major diameter
2.Minor diameter
3.Pitch diameter
4.Core diameter
The fatigue life of a part can be improved by
1.Electroplating
2.Polishing
3.Coating
4.Shot peening
The included angle for the British Association thread is
1. 29°
2.55°
3.47.3°
4.60°
The lower deviation is the algebraic difference between the
1.Actual size and the corresponding basic size
2.Maximum limit and the basic size
3.Minimum limit and the basic size
4.All of the above
The maximum normal stress theory is used for
1. Plastic materials
2. Brittle materials
3.Non-ferrous materials
4.Ductile materials
The number of slots in a 25 mm castle nut is
1.8
2.4
3.2
4.6
The piston rod of a steam engine is usually connected to the cross-head by means of
1.Bolted joint
2.Knuckle joint
3. Cotter joint
4.Universal joint
The rated life of a bearing varies
1.Directly as load
2. Inversely as square of load
3.Inversely as cube of load
4.Inversely as fourth power of load
The ratio of endurance limit in shear to the endurance limit in flexure is
1. 0.70
2. 0.25
3.0.40
4.0.55
The rivet head used for boiler plate riveting is usually
1.Pan Head
2.Snap head
3.Counter sunk head
4. Conical head
The usual clearance provided in hydrodynamic bearing per mm of diameter of shaft is
1.0.01 micron
2.0.1 micron
3.1 micron
4.10 microns
Three different weights fall from a certain height under vacuum. They will take
1.Same time to reach earth
2.Times proportional to weight to reach earth
3. Times inversely proportional to weight to reach earth
4.None of the above
When a close coiled helical spring is compressed, its wire is subjected to
1. Tension
2.Shear
3.Compression
4.All of the above
When the bearing is subjected to large fluctuations of load and heavy impacts, the bearing characteristic number should be _________ the bearing modulus.
1.10 times
2.5 times
3.15 times
4.20 times
When the belt speed increases
1.Power transmitted increases
2. Power transmitted decreases
3. Power transmitted increases to a maximum value and then decreases
4.Power transmitted remains the same
When two helical springs of equal lengths are arranged to form a cluster spring, then
1.Shear stress in each spring will be equal
2.Load taken by each spring will be half the total load
3.Only A is correct
4. Both A and B is correct
Which is correct statement?
1.A member made of steel will generally be more rigid than a member of equal load carrying ability made of cast iron
2. A member made of cast iron will generally be more rigid than a member of equal load carrying ability made of steel
3.Both will be equally rigid
4.Which one is rigid will depend on several other factors
Which is positive drive?
1.Flat belt drive
2.V belt drive
3.Crossed belt drive
4.Timing belt
Which of the following material has the maximum ductility?
1.Copper
2.Mild steel
3.Aluminium
4.Zinc
Which of the following pipe joints would be suitable for pipes carrying steam?
1.Flanged
2.Threaded
3.Bell and spigot
4.Expansion