The steel pulleys are __________ in weight than cast iron pulleys of the same capacity.
Heavier
Lighter
Moderate
None of these
Correct Answer :
B. Lighter
Related Questions
According to I.B.R., shearing resistance required to shear off the rivet per pitch length (in double shear) is (where n = Number of rivets per pitch length)
(π/4) d² × τ × n
1.875 × (π/4) d² × τ × n
2 × (π/4) d² × τ × n
3 × (π/4) d² × τ × n
A connecting rod should be
Strong in buckling about X-axis
Strong in buckling about Y-axis
Equally strong in buckling about X-axis and Y-axis
Any one of the above
For a shoe brake, the equivalent coefficient of friction is equal to (where μ = Actual coefficient of friction, and θ = Semi-block angle)
2μ sinθ/(θ + sinθ)
μ sinθ/(2θ + sin 2θ)
4μ sinθ/(θ + sinθ)
4μ sinθ/(2θ + sin 2θ)
The maximum shear stress theory is used for
Brittle materials
Ductile materials
Plastic materials
Nonferrous materials
A key made from a cylindrical disc having segmental cross-section, is known as
Woodruff key
Feather key
Flat saddle key
Gib head key
According to I.B.R., the efficiency of a triple riveted butt joint with double straps of unequal width (5 rivets per pitch length) should be
45 to 60 %
63 to 70 %
70 to 83 %
80 to 90 %
Fibrous fracture occurs in
Ductile material
Brittle material
Elastic material
Hard material
In a marine flange coupling, the thickness of flange is taken as
d/2
d/3
3d/4
d/4
The maximum efficiency of a square threaded screw is
(1 - sinφ)/ (1 + sinφ)
(1 + sinφ)/ (1 - sinφ)
(1 - sinφ)/ (1 + cosφ)
(1 + cosφ)/ (1 - sinφ)
Brittle coating technique is used for
Determining brittleness
Protecting metal against corrosion
Protecting metal against wear and tear
Experimental stress analysis
A crankshaft is a __________ shaft.
Transmission
Machine
Machine frame
None of these
The shock absorbing capacity of a bolt can be increased by
Tightening it properly
Increasing shank diameter
Grinding the shank
Making shank diameter equal to core diameter of thread.
Which of the following screw thread is used for power transmission in one direction only?
Square threads
Multiple threads
Acme threads
Buttress threads
According to I.B.R., the efficiency of a double riveted butt joint with double cover straps of equal width should be
45 to 60 %
63 to 70 %
70 to 83 %
80 to 90 %
The connecting rod bolts are tightened up so that tightening stress
Is just sufficient to hold parts together
Approaches yield point
Is 50% of yield point
Is about yield point divided by safety factor
In an oil lubricated journal bearing, the coefficient of friction between the journal and the bearing
Remains constant at all speeds
Is minimum at zero speed and increases monotonically with increase in speed
Is maximum at zero speed and decreases monotonically with increase in speed
Becomes minimum at an optimum speed and then increases with further increase in speed
When two helical springs of equal lengths are arranged to form a cluster spring, then
Shear stress in each spring will be equal
Load taken by each spring will be half the total load
Only A is correct
Both A and B is correct
If an application calls for stresses on screw threads in one direction only, then the following type of thread would be best suited
Square
Acme
Buttress
BSW
The arms of the pulleys for flat belt drive have
Elliptical cross-section
Major axis in plane of rotation
Major axis twice the minor axis
All the three characteristics
In designing a sleeve coupling, length of the sleeve is taken as (where d = Diameter of the shaft)
d + 17 mm
2d + 13 mm
2d + 20 mm
3.5d
In testing a material for endurance strength, it is subjected to
Static load
Dynamic load
Impact load
Completely reversed load
Whether any core is required in wire ropes
Yes
No
Sometimes
Rarely
The ultimate strength of steel in tension in comparison to shear is in the ratio of
1 : 1
2 : 1
3 : 2
2 : 3
A screw is said to be a self locking screw, if its efficiency is
Less than 50 %
More than 50 %
Equal to 50 %
None of these
Creep in belt is due to
Material of the belt
Material of the pulley
Uneven extensions and contractions due to varying tension
All of the above
During hot working of metals,
Porosity of the metal is largely eliminated
Grain structure of the metal is refined
Mechanical properties are improved due of refinement of grains
All of the above
The application of third type levers is found in
A pair of tongs
Hand wheel of a punching press
Lever of a loaded safety valve
Handle of a hand pump
In V-belt drive, belt touches
At bottom
At sides only
Both at bottom and sides
Could touch anywhere
The face of the tooth is the
Surface of the top of the tooth
Surface of the tooth above the pitch surface
Surface of the tooth below the pitch surface
Width of the tooth measured along the pitch circle
The circumferential and longitudinal strains in a cylindrical boiler under internal steam pressure are εc and εl respectively. The change in volume of the boiler cylinder per unit volume will be
εc + 2εl
2εc + εl
εc + εl²
εc² + εl