A hot short metal is
1.Brittle when cold
2.Brittle when hot
3.Brittle under all conditions
4.Ductile at high temperature
According to Indian standard specifications, 100 H6/g5 means that the
1.Basic size is 100 mm
2.Actual size is 100 mm
3.Difference between the actual size and basic size is 100 mm
4.None of these
Brittle coating technique is used for
1.Determining brittleness
2.Protecting metal against corrosion
3.Protecting metal against wear and tear
4. Experimental stress analysis
For steel, the ultimate strength in shear as compared to ultimate strength in tension is
1.1/2
2.1/3
3.1/4
4. 2/3
Guest's theory of failure is applicable for following type of materials
1. Brittle
2.Ductile
3.Elastic
4.Plastic
If a load W is applied instantaneously on a bar; Then the stress induced in bar will
1. Be independent of ratio of mass of load W to mass of bar (y)
2. Increase with increase in y
3.Decrease with decrease in y
4.Depend on other considerations
In a flange coupling, the flanges are coupled together by means of
1.Bolts and nuts
2.Studs
3.Headless taper bolts
4.None of these
In case of pressure vessels having closed ends, the fluid pressure induces
1.Longitudinal stress
2.Shear stress
3.Circumferential stress
4.None of these
In most machine members, the damping capacity of the material should be
1.Low
2.Zero
3.High
4.Could be anything
In order to avoid tearing of the plate at an edge, the distance from the centre line of the rivet hole to the nearest edge of the plate should be equal to (where d = Diameter of rivet hole)
1.d
2.1.5 d
3.2.5 d
4.2 d
In radial cams, the follower moves
1.In a direction parallel to the cam axis
2.In a direction perpendicular to the cam axis
3.In any direction irrespective of cam axis
4.Along the cam axis
In replacing the V-belts, a complete set of new belts is used instead of replacing a single damaged belt because
1.Belts are available in sets
2.Only one belt cannot be fitted with other used belts
3.The new belt will carry more than its share and result in short life
4.New and old belts will cause vibrations
In unilateral system of tolerance, the tolerance is allowed on
1.Both sides of the actual size
2.One side of the actual size
3.One side of the nominal size
4.Both sides of the nominal size
The belt slip occurs due to
1. Heavy load
2.Loose belt
3.Driving pulley too small
4.Any one of the above
The constant factor in case of R10 series of preferred numbers is
1. 1.06
2.1.12
3.1.26
4.1.58
The endurance limit of a material with finished surface in comparison to rough surface is
1.More
2.Same
3.Less
4.More or less depending on quantum of load
The load cup of a screw jack is made separate from the head of the spindle to
1.Prevent the rotation of load being lifted
2.Enhance the load carrying capacity of the jack
3. Reduce the effort needed for lifting the working load
4.Reduce the value of frictional torque
The number of slots in a 25 mm castle nut is
1.8
2.6
3.4
4.2
The power transmitted by the belt drive can be increased by
1. Increasing the initial tension in the belt
2.Dressing the belt to increase the coefficient of friction
3.Increasing wrap angle by using idler pulley
4.All of the above methods
The ratio of endurance limit in shear to the endurance limit in flexure is
1. 0.33
2.0.4
3.0.5
4.0.55
The rolling contact bearings are known as
1.Thick lubricated bearings
2.Plastic bearings
3.Antifriction bearings
4.Thin lubricated bearings
The sleeve or muff coupling is designed as a
1.Dun cylinder
2.Hollow shaft
3.Solid shaft
4.Thick cylinder
The value of stress concentration factor depends upon
1.Material and geometry of the part
2.Geometry of the part
3.Material of the part
4.None of these
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
1.Crown bevel gears
2.Angular bevel gears
3.Mitre gears
4.Internal bevel gears
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
1.Angular bevel gears
2.Mitre gears
3.Internal bevel gears
4.Crown bevel gears
Which of the following screw thread is used for power transmission in one direction only?
1.Square threads
2.Multiple threads
3.Acme threads
4.Buttress threads
. Stress concentration in cyclic loading is more serious in
1.Ductile materials
2.Brittle materials
3. Equally serious in both cases
4.Depends on other factors
A transmission shaft includes
1.Over head shaft
2.Counter shaft
3.Line shaft
4. All of these
A V-belt designated as B 4430 LP has
1. 4430 mm as diameter of small pulley
2.4430 mm as nominal pitch length
3.4430 mm as diameter of large pulley
4.4430 mm as centre distance between pulleys
An Involute pinion and gear are in mesh. If both have the same size of addendum, then there will be interference between the
1.Tip of the pinion and flank of gear
2.Tip of the gear and flank of pinion
3.Flanks of both gear and pinion
4.Tip of both gear and pinion
Coaxing is the procedure of increasing
1.Metal strength by cycling
2.Metal hardness by surface treatment
3.Metal resistance to corrosion by coating
4.Fatigue limit by over-stressing the metal by successively increasing loadings
Cold working
1.Increases the fatigue strength
2.Decreases the fatigue strength
3.Has no influence on fatigue strength
4.Alone has no influence on fatigue strength
Endurance limit or fatigue limit is the maximum stress that a member can withstand for an infinite number of load applications without failure when subjected to
1.Dynamic loading
2.Static loading
3. Combined static and dynamic loading
4. Completely reversed loading
For unequal width of butt straps, the thicknesses of butt straps are
1.0.75 t for narrow strap on the inside and 0.625 t for wide strap on the outside
2.0.75 t for wide strap on the inside and 0.625 t for narrow strap on the outside
3.0.75 t for both the straps on the inside and outside
4.0.625 t for both the straps on the inside and outside
In a marine flange coupling, the thickness of flange is taken as
1.d/2
2.d/3
3.3d/4
4.d/4
In nitrated parts, the origins of the fatigue cracks will occur at
1.Surface
2.Just below the surface
3. Within the core
4.None of above
In radial cams, the follower moves
1.In a direction parallel to the cam axis
2.In a direction perpendicular to the cam axis
3. In any direction irrespective of cam axis
4.Along the cam axis
In Vickers hardness testing, the pyramid indentor apex is
1.40°
2.122°
3.136°
4.152°
Pick up wrong statement. Fatigue strength can be increased by
1.Cold working
2.Shot peening
3.Grinding and lapping surface
4.Hot working
Plastic flow in ductile materials
1.Increases the seriousness of static loading stress concentration
2.Lessens the seriousness of static loading stress concentration
3.Has no effect on it
4.Depends on other considerations
Rankine's theory of failure is applicable for following type of materials
1.Brittle
2.Ductile
3.Elastic
4.Plastic
Residual stress in materials
1.Acts when external load is applied
2.Becomes zero when external load is removed (C)
3. Is independent of external loads
4.Is always harmfu
Resilience of a material is important, when it is subjected to
1. Combined loading
2.Fatigue
3.Thermal stresses
4.Shock loading
Screws used for power transmission should have
1.Very fine threads
2. High efficiency
3.Low efficiency
4.Strong teeth
Slenderness ratio is the ratio of
1.Effective length of column to least radius of gyration of the column
2.Width of column to depth of column
3.Maximum size of column to minimum size of column
4.Effective length of column to width of column
Stress concentration is caused due to
1.Variation in properties of material from point to point in a member
2.Pitting at points or areas at which loads on a member are applied
3.Abrupt change of section
4.All of the above
Surface endurance limit of gear material is dependent upon its
1.Elastic strength
2.Yield strength
3.Brinell hardness number
4.Toughness
Tensile strength of a mild steel specimen can be roughly predicted from following hardness test
1.Brinell
2.Rockwell
3.Vickers
4.None of the above
The arms of the pulleys for flat belt drive have
1.Elliptical cross-section
2.Major axis in plane of rotation
3.Major axis twice the minor axis
4.All the three characteristics
The backlash for spur gears depends upon
1.Module
2.Tooth profile
3.Both module and pitch line velocity
4. Pitch line velocity
The building up of worn and undersized parts, subjected to repeated loads by electroplating is
1.Best method
2.Extremely hazardous
3.Has no effect as regards fatigue strength
4.Cheapest method
The centrifugal tension in belts
1. Decreases the power transmitted
2.Increases the power transmitted
3.Increase the wrap angle
4.Increases the belt tension without increasing power transmission
The cracks in helical springs used in railway carriages usually start on the inner side of the coil because of the fact that
1.It is subjected to a higher cyclic loading than the outer side
2.It is subjected to a higher stress than the outer side
3.It is more stretched than the outer side during the manufacturing process
4.It has a lower curvature than the outer side
The groove angle of pulleys for V-belt is
1.340 to 360
2.420 to 450
3.More than 400
4.300 to 320
The notch angle of the Izod impact test specimen is
1.10°
2.20°
3.30°
4.45°
The objective of idler pulley in belt drive is to
1.Decrease the tendency of belt to slip
2.Increase the power transmission capacity
3.Increase the wrap angle and belt tension
4.All the above objectives
The permissible stress for carbon steel under static loading is generally taken as
1.2000-3000 kg/m²
2.3000-4000 kg/cm²
3.4000-4500 kg/cm²
4.7500-10,000 kg/cm²
The property of a material which enables it to resist fracture due to high impact loads is known as
1.Elasticity (B) (C) (D)
2.Endurance
3.Strength
4.Toughness
The rolling contact bearings are known as
1.Thick lubricated bearings
2.Plastic bearings
3.Antifriction bearings
4.Thin lubricated bearings
The size of a gear is usually specified by
1.Pressure angle
2.Pitch circle diameter
3. Circular pitch
4.Diametral pitch
The toughness of a material _________ when it is heated
1.Does not change
2.Increases
3.Decreases
4.None of these
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
1.Angular bevel gears
2.Mitre gears
3.Internal bevel gears
4.Crown bevel gears
When screw threads are to be used in a situation where power is being transmitted in one direction only, then the screw threads suitable for this will be
1.Knuckle threads
2.Square threads
3.Acme threads
4.Buttress threads
When the speed of belt increases,
1.The coefficient of friction between the belt and pulley decreases
2.The coefficient of friction between the belt and pulley increases
3.The power transmitted will decrease
4.The power transmitted will increase
Which is correct statement? Stress concentration in static 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
Which of the following is not correct procedure to increase the fatigue limit?
1.Cold working
2.Shot peening
3. Surface decarburisation
4.Under stressing
Which of the following statement is correct for gears?
1.The pitch circle diameter is equal to the product of module and number of teeth
2.The addendum is less than dedendum
3. The pitch circle is always greater than the base circle
4.All of the above
Which one of the following is a positive drive?
1.V-belt drive
2.Rope drive
3.Crossed flat belt drive
4.Chain drive
Which process will increase the fatigue duration of parts?
1. Finishing and polishing
2.Shot-peening
3.De-carburisation
4.Electroplating
Yield point in fatigue loading as compared to static loading is
1.Same
2.Higher
3.Lower
4.Depends on other factors