The building up of worn and undersized parts, subjected to repeated loads by electroplating is
Best method
Extremely hazardous
Has no effect as regards fatigue strength
Cheapest method
Correct Answer :
A. Best method
Related Questions
The rolling contact bearings as compared to sliding contact bearings have
Low starting and low running friction except at very high speeds
Accuracy of shaft alignment
Small overall dimensions
All of the above
When the length of the journal is equal to the diameter of the journal, then the bearing is said to be a
Short bearing
Long bearing
Medium bearing
Square bearing
Buttress threads are usually found on
Screw cutting lathes
Feed mechanisms
Spindles of bench vices
Railway carriage couplings
The shear stress in a beam varies from zero at the outer fibres to a maximum at the________.
Neutral surface
Upper surface
Lower surface
None of these
A universal coupling is used to connect two shafts
Which are not in exact alignment
Which are perfectly aligned
Whose axes intersect at a small angle
Have lateral misalignment
In cross or regular lay ropes
Direction of twist of wires in strands is opposite to the direction of twist of strands
Direction of twist of wires and strands are same
Wires in two adjacent strands are twisted in opposite direction
Wires are not twisted
The shear stress at a point in a shaft subjected to a torque is
Directly proportional to the polar moment of inertia and to the distance of the point from the axis
Directly proportional to the applied torque and inversely proportional to the polar moment of inertia
Directly proportional to the applied torque and the polar moment of inertia
Inversely proportional to the applied torque and the polar moment of inertia
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
For general industrial machinery, the ratio of the length of journal to its diameter is taken as
0.5 to 1
1 to 2
3 to 5
5 to 10
Oldham coupling is used to connect two shafts
Which are perfectly aligned
Which are not in exact alignment
Which have lateral misalignment
Whose axes intersect at a small angle
The ratio of driving tensions for flat belts, neglecting centrifugal tension, is (where T₁, and T₂ = Tensions on the tight and slack sides of belt respectively, μ = Coefficient of friction, between the belt and pulley, and θ = Angle of contact)
T₁/T₂ = μθ
log (T₁/T₂) = μθ
T₁/T₂ =eμθ
T₁/T₂ = log μθ
A shaft is subjected to fluctuating loads for which the normal torque (T) and bending moment (M) are 1000 N-m and 500 N-m respectively. If the combined shock and fatigue factor for bending is 1.5 and combined shock and fatigue factor for torsion is 2, then the equivalent twisting moment for the shaft is
2000 N-m
2050 N-m
2100 N-m
2136 N-m
In radial bearings, the load acts __________ to the axis of rotation.
Parallel
Perpendicular
Both A and B
None of these
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
Belt slip may occur due to
Heavy load
Loose belt
Driving pulley too small
All of the above
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
ZN/p
p/ZN
Z/pN
N/Zp
When the screw in a mechanical screw jack rotates, the load kept on the top of it moves
Axially upwards
Axially downwards
Axially upwards or downwards
None of these
Fibrous fracture occurs in
Ductile material
Brittle material
Elastic material
Hard material
The velocity of sliding ________ the distance of the point of contact from the pitch point.
Is directly proportional to
Is inversely proportional to
Is equal to cos φ multiplied by
Does not depend upon
Tearing resistance required to tear off the plate per pitch length is (where p = Pitch of rivets, d = Dia. of rivet hole, and σt = Permissible tensile stress for plate material)
p.d.σt
p.t.σt
(p - d) σt
(p - d) t.σt
A bolt of uniform strength can be developed by
Keeping the core diameter of threads equal to the diameter of unthreaded portion of the bolt
Keeping the core diameter smaller than the diameter of the unthreaded portion
Keeping the nominal diameter of threads equal to the diameter of unthreaded portion of the bolt
None of the above
The design of shafts made of brittle materials is based on
Guest's theory
Rankine's theory
St Venant's theory
Von Mises theory
Crushing resistance required to crush the rivet per pitch length is
p.d.σc
p.t.σc
n.d.t.σc
(p - d) t.σc
In worm gears, the pressure angle is ________ the angle between two inclined faces in axial plane.
Half
Twice
Thrice
None of these
A self locking screw has
Fine threads
Course threads
Coefficient of friction is greater than tangent of load angle
Hole for inserting split pin
Pick up wrong statement. Fatigue strength can be increased by
Cold working
Shot peening
Grinding and lapping surface
Hot working
The velocity factor for ordinary cut gears operating at velocities upto 12.5 m/s is equal to
0.75/ (0.75 + √v)
3/ (3 + v)
4.5/ (4.5 + v)
6/ (6 + v)
The bending stress in a curved beam is
Zero at the centroidal axis
Zero at the point other than centroidal axis
Maximum at the neutral axis
None of these
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
When a belt drive is transmitting maximum power,
Effective tension is equal to centrifugal tension
Effective tension is half of centrifugal tension
Driving tension on slack side is equal to centrifugal tension
Driving tension on tight side is twice the centrifugal tension