In order to ensure self locking in a screw jack, it is essential that helix angle is __________ friction angle.
Larger than
Smaller than
Equal to
None of these
Correct Answer :
B. Smaller than
Related Questions
A screw is said to be over hauling screw, if the
Friction angle is less than helix angle
Friction angle is more than helix angle
Friction angle is equal to helix angle
Efficiency of screw is 100%
In case of V-belt drive
The belt should touch the bottom of groove in the pulley
The belt should not touch the bottom of groove in the pulley
The belt should not touch the sides of groove in the pulley
None of the above
The strap end of a connecting rod of steam engine is joined by
Gib of cotter joint
Sleeve and cotter joint
Spigot socket cotter joint
Knuckle joint
The radial distance of a tooth from the pitch circle to the top of the tooth is called
Addendum
Dedendum
Clearance
Working depth
In cylindrical cams, the follower moves
In a direction perpendicular to the cam axis
In a direction parallel to the cam axis
In any direction irrespective of cam axis
Along the cam axis
In a boundary lubricated bearing, there is a __________ of lubricant between the journal and the bearing.
Thick film
Thin film
Either A or B
None of these
In order to avoid tearing of the plate at edge, the distance from the center line of the rivet hole to the nearest edge of the plate in terms of dia. of rivet d should be equal to
d
1.25 d
1.5 d
1.75 d
The belt slip occurs due to
Heavy load
Loose belt
Driving pulley too small
Any one of the above
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
Stress concentration is caused due to
Variations in load acting on a member
Variations in properties of materials in a member
Abrupt change of cross-section
All of these
The number of slots in a 25 mm castle nut is
8
6
4
2
The effective stress in wire ropes during normal working is equal to the stress due to
Axial load plus stress due to bending
Acceleration/retardation of masses plus stress due to bending
Axial load plus stress due to acceleration/retardation
Bending plus stress due to acceleration/retardation
The objective of caulking in a riveted joint is to make the joint
Free from corrosion
Stronger in tension
Free from stress
Leak-proof
The rivet head used for boiler plate riveting is usually
Pan Head
Snap head
Counter sunk head
Conical head
Which of the following statement is correct, for two shafts connected in parallel?
Torque in each shaft is the same
Shear stress in each shaft is the same
Angle of twist of each shaft is the same
Torsional stiffness of each shaft is the same
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
The yield point in static loading is __________ as compared to fatigue loading.
Higher
Lower
Same
None of these
The angle of twist of shaft is
Directly proportional to (shaft diameter)²
Inversely proportional to (shaft diameter)²
Directly proportional to (shaft diameter)⁴
Inversely proportional to (shaft diameter)⁴
The helix angle for single helical gears ranges from
10° to 15°
15° to 20°
20° to 35°
35° to 50°
Which is positive drive?
Flat belt drive
V-belt drive
Crossed belt drive
Timing belt
A special case of ductility which permits materials to be rolled or hammered into thin sheets, is called
Plasticity
Elasticity
Ductility
Malleability
In composite or reverse laid 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 power transmitted by belt drive depends upon
Belt velocity
Initial belt tension
Arc of contact
All of the above
The notch sensitivity q is expressed in terms of fatigue stress concentration factor Kf and theoretical stress concentration factor Kt as
(Kf + 1)/ (Kt + 1)
(Kf - 1)/ (Kt - 1)
(Kt + 1)/ (Kf + 1)
(Kt - 1)/ (Kf - 1)
Turn buckle has
Right hand threads on bout ends
Left hand threads on both ends
Left hand threads on one end and right hand threads on other end
No threads
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
A key made from a cylindrical disc having segmental cross-section, is known as
Woodruff key
Feather key
Flat saddle key
Gib head key
The process extensively used for making bolts and nuts is
Hot piercing
Extrusion
Cold peening
Cold heading
A sliding bearing in which although lubricant is present, the working surfaces __________ contact each other at least part of the time, is called boundary lubricated bearing.
Partially
Fully
Either A or B
None of these
Tapered roller bearings can take
Axial load only
Both radial and axial loads and the ratio of these being greater than unity
Radial load only
Both radial and axial loads and the ratio of these being less than unity