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
Correct Answer :
A. ZN/p
Related Questions
In a journal bearing, the load on the bearing is __________ to the axis of the journal.
Parallel
Perpendicular
Both A and B
None of these
A compound cylinder with inner radius 50 mm and outer radius 70 mm is made by shrinking one cylinder on to the other cylinder, the junction radius is 60 mm and the junction pressure is 1.1 N/mm². The maximum hoop stress developed in the inner cylinder is
3.6 N/mm² compression
3.6 N/mm² tension
7.2 N/mm² compression
7.2 N/mm² tension
Eulers formula for a mild steel column is not valid if the slenderness ratio is
90
60
120
100
The shearing stresses in the inner face as compared to outer face of the wire in a heavy close coiled spring is
Larger
Smaller
Equal
Larger/smaller depending on diameter of spring coil
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 temperature at which the new grains are formed in the metal is known as
Lower critical temperature
Upper critical temperature
Recrystallisation temperature
None of these
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
A triple riveted butt joint with double straps of unequal width is to be designed for a boiler shell. The pitch of the rivets in the outer row is double the pitch in the inner row and zigzag riveting is proposed. Which of the following statement is correct?
There are four rivets per pitch length, all in double shear
There are four rivets per pitch length, out of which two are in single shear and two are in double shear
There are five rivets per pitch length, all in double shear
There are five rivets per pitch length, out of which four are in double shear and one is in single shear
In a transverse fillet welded joint, the size of weld is __________ the throat of weld.
0.5 times
Equal to
2 times
Double
Which of the following statement is correct?
The distance from a point on one thread to the corresponding point on the next thread is called pitch
The distance which a screw thread advances axially in one rotation of the nut is called lead
In single start threads, lead is equal to pitch
All of the above
The coefficient of friction in belt drive depends upon
Material of belt
Material of pulley
Materials of belt and pulley
Belt velocity
When spring index increases, the value of Wahl's stress factor
Increases linearly
Decreases linearly
Remains same
Increases exponentially
A single strap butt joint is always in __________ shear.
Single
Double
Triple share
None of these
The edges of a boiler plate are bevelled to an angle of
30°
45°
60°
80°
When an open coiled helical compression spring is subjected to an axial compressive load, the maximum shear stress induced in the wire is (where D = Mean diameter of the spring coil, d = Diameter of the spring wire, K = Wahl's stress factor, and W = Axial compressive load on the spring)
(WD/ πd3) × K
(2WD/ πd3) × K
(4WD/ πd3) × K
(8WD/ πd3) × K
For steel, the ultimate strength in shear as compared to ultimate strength in tension is
1/2
1/3
1/4
2/3
A hollow saddle key is
A taper key which fits half in the key way of hub and half in the key way of shaft
A taper key which fits in a key way of the hub and is flat on the shaft
A taper key which fits in a key way of the hub and the bottom of the key is shaped to fit the curved surface of the shaft
Provided in pairs at right angles and each key is to withstand torsion in one direction only
In a flange coupling, the flanges are coupled together by means of
Bolts and nuts
Studs
Headless taper bolts
None of these
The design of pin of a rocker arm of an I.C. engine is based on
Bearing failure
Shearing failure
Bending failure
All of these
According to Indian standard specifications, 100 H6/g5 means that the
Basic size is 100 mm
Actual size is 100 mm
Difference between the actual size and basic size is 100 mm
None of the above
In thrust bearings, the load acts
Along the axis of rotation
Parallel to the axis of rotation
Perpendicular to the axis of rotation
In any direction
The included angle in unified of American National threads is
60°
55°
47°
29°
Rankine's theory is used for
Brittle materials
Ductile materials
Elastic materials
Plastic materials
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
A self locking screw has
Fine threads
Course threads
Coefficient of friction is greater than tangent of load angle
Hole for inserting split pin
The design of shafts made of brittle materials is based on
Guest's theory
Rankine's theory
St Venant's theory
Von Mises theory
Which of the following statement is wrong?
A key is used as a temporary fastening
A key is subjected to tensile stresses
A key is always inserted parallel to the axis of the shaft
A key prevents relative motion between the shaft and boss of the pulley
Gear box is used
To produce torque
For speed reduction
To obtain variable speeds
To increase efficiency of system
The maximum normal stress theory is used for
Plastic materials
Brittle materials
Non-ferrous materials
Ductile materials
The constant factor in case of R10 series of preferred numbers is
1.06
1.12
1.26
1.58