Idler pulley is used for
Increasing velocity ratio
For applying tension
Changing the direction of motion of belt
All of these
Correct Answer :
B. For applying tension
Related Questions
The shear plane in case of bolts should
Be across threaded portion of shank
Be parallel to axis of bolt
Be normal to threaded portion of shank
Never be across the threaded portion
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
Tensile strength of a mild steel specimen can be roughly predicted from following hardness test
Brinell
Rockwell
Vickers
None of the above
If two springs are in parallel then their overall stiffness will be
Half
Same
Double
None of the above
In a steam engine, the piston rod is usually connected to the crosshead by means of a
Knuckle joint
Cotter joint
Oldham coupling
Universal joint
According to Indian standards, a bolt thread of 6 mm size of coarse pitch and with allowance on the threads and normal tolerance grade is designated as
M6
M8
M6 - 8d
M8 - 6d
Which of the following statement is correct regarding power screws?
The efficiency of a self locking screw can not be more than 50%
The efficiency of Acme (trapezoidal) thread is less than that of a square thread
If the friction angle is less than the helix angle of the screw, then the efficiency will be more than 50%
(A) and (B) Only
In helical gears, the distance between similar faces of adjacent teeth along a helix on the pitch cylinders normal to the teeth, is called
Normal pitch
Axial pitch
Diametral pitch
Module
A key made from a cylindrical disc having segmental cross-section, is known as
Woodruff key
Feather key
Flat saddle key
Gib head key
Cast iron pipes are mainly used
For conveying steam
In water and sewage systems
In pressure lubrication systems on prime movers
All of the above
Oil in journal bearing should be applied at the point where load is
Nil or lightest
Maximum
Average
Any one of the above
A type of brake commonly used in motor cars is a
Shoe brake
Band and block brake
Band brake
Internal expanding brake
Taper on the cotter and slot is provided
On both the sides
On one side only
On none of the sides
May be provided anywhere
The stress induced in the belt is,
Tensile stress
Compressive stress
Direct shear stress
Torsional shear stress
The centre to centre distance between two consecutive rivets in a row, is called
Margin
Pitch
Back pitch
Diagonal pitch
The minimum number of teeth on the pinion which will mesh with any gear without interference for 20° full depth involute teeth will be
12
14
18
24
The cold working of metals is carried out __________ the recrystallisation temperature.
Above
Below
At
None of these
For applications involving high stresses in one direction only the following type of thread would be best suited
ISO metric thread
Acme thread
Square thread
Buttress thread
The pitch of threads on a Jock nut in comparison to pitch of nut is
Same
Coarser
Finer
Very fine
For a shaft diameter of 200 mm, the number of bolts in a marine flange coupling should be
8
6
4
10
A feather key is generally
Loose in shaft and tight in hub
Tight in shaft and loose in hub
Tight in both shaft and hub
Loose in both shaft and hub
Set screws are
Similar to small size tap bolts except that a greater variety of shapes of heads are available
Slotted for a screw driver and generally used with a nut
Used to prevent relative motion between parts
Similar to stud
The material generally used for aircraft components is
Mild steel
High speed steel
Stainless steel
Aluminium
The cracks in helical springs used in railway carriages usually start on the inner side of the coil because of the fact that
It is subjected to a higher cyclic loading than the outer side
It is subjected to a higher stress than the outer side
It is more stretched than the outer side during the manufacturing process
It has a lower curvature than the outer side
Fibrous fracture occurs in
Ductile material
Brittle material
Elastic material
Hard material
The helix angle for double helical gears may be made up to
45°
60°
75°
90°
In leaf springs, the longest leaf is known as
Master leaf
Lower leaf
Upper leaf
None of these
In radial bearings, the load acts __________ to the axis of rotation.
Parallel
Perpendicular
Both A and B
None of these
In V-belt drive, belt touches
At bottom
At sides only
Both at bottom and sides
Could touch anywhere
The tension on the slack side of the belt is __________ the tension on the tight side of the belt.
Equal to
Less than
Greater than
None of these