The objective of idler pulley in belt drive is to
Decrease the tendency of belt to slip
Increase the power transmission capacity
Increase the wrap angle and belt tension
All the above objectives
Correct Answer :
D. All the above objectives
Related Questions
In a band and block brake, the ratio of tensions on the tight and slack sides of band is given by (where μ = Coefficient of friction between the blocks and the drum, θ = Semi-angle of each block subtending at the centre of drum, and n = Number of blocks)
T₁/T₂ = μθ × n
T₁/T₂ = (μθ)n
T₁/T₂ = [(1 - μ tanθ)/ (1 + μ tanθ)]n
T₁/T₂ = [(1 + μ tanθ)/ (1 - μ tanθ)]n
The load cup of a screw jack is made separate from the head of the spindle to
Prevent the rotation of load being lifted
Enhance the load carrying capacity of the jack
Reduce the effort needed for lifting the working load
Reduce the value of frictional torque
Maximum principal stress theory is applicable for
Ductile materials
Brittle materials
Elastic materials
All of the above
The application of third type levers is found in
Handle of a hand pump
Hand wheel of a punching press
Lever of a loaded safety valve
A pair of tongs
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
Fibrous fracture occurs in
Ductile material
Brittle material
Elastic material
Hard material
In a transverse fillet welded joint, the size of weld is __________ the throat of weld.
0.5 times
Equal to
2 times
Double
A leaf spring in automobiles is used
To apply forces
To measure forces
To absorb shocks
To store strain energy
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
Brittle coating technique is used for
Determining brittleness
Protecting metal against corrosion
Protecting metal against wear and tear
Experimental stress analysis
The sleeve or muff coupling is designed as a
Dun cylinder
Hollow shaft
Solid shaft
Thick cylinder
Which of the following property is essential for spring materials?
Stiffness
Ductility
Resilience
Plasticity
Which of the following statement is correct for gears?
The pitch circle diameter is equal to the product of module and number of teeth
The addendum is less than dedendum
The pitch circle is always greater than the base circle
All of the above
In Vickers hardness testing, the pyramid indentor apex is
40°
122°
136°
152°
Which is correct statement? Stress concentration in static loading is
Very serious in brittle materials and less serious in ductile materials
Very serious in ductile materials and less serious in brittle materials
Equally serious in both types of materials
Seriousness would depend on other factors
The velocity factor for very accurately cut and ground metallic gears operating at velocities upto __________ are equal to 6/(6 + v).
10 m/s
12.5 m/s
15 m/s
20 m/s
For circumferential joint in boilers, the type of joint used is
Butt joint with single cover plate
Butt joint with double cover plate
Lap joint with one ring overlapping the other
Any one of the above
In a marine flange coupling, the thickness of flange is taken as
d/2
d/3
3d/4
d/4
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
Three different weights fall from a certain height under vacuum. They will take
Same time to reach earth
Times proportional to weight to reach earth
Times inversely proportional to weight to reach earth
None of the above
Which of the following screw thread is used for power transmission in one direction only?
Square threads
Multiple threads
Acme threads
Buttress threads
In skew bevel gearing, the axes of shafts are
Intersecting and the teeth are curved
Non-intersecting and nonparallel and the teeth are curved
Non-intersecting and non-parallel and the teeth are straight
None of the above
Two shafts A and B are made of the same material. The diameter of shaft A is twice as that of shaft B. The power transmitted by the shaft A will be __________ of shaft B.
Twice
Four times
Eight times
Sixteen times
Jam nut is a locking device in which
One smaller nut is tightened over main nut and main nut tightened against smaller one by loosening, creating friction jamming
A slot is cut partly in middle of nut and then slot reduced by tightening a screw
A hard fibre or nylon cotter is recessed in the nut and becomes threaded as the nut is screwed on the bolt causing a tight grip
Through slots are made at top and a cotter pin is passed through these and a hole in the bolt, and cotter spitted and bent in reverse direction at other end
Form coefficient of spring is
Ratio of coil diameter to wire diameter
Load required to produce unit deflection
Its capability of storing energy
Concerned with strength of wire of spring
Whether any core is required in wire ropes
Yes
No
Sometimes
Rarely
When bevel gears having equal teeth and equal pitch angles connect two shafts whose axes intersect at right angle, then they are known as
Angular bevel gears
Crown bevel gears
Internal bevel gears
Mitre gears
When the belt is transmitting maximum power,
The tension in tight side is twice the centrifugal tension
The tension in slack side is equal to the centrifugal tension
The tension in tight side is thrice the centrifugal tension
None of the above
Wahl's stress factor __________ very rapidly as the spring index decreases.
Increases
Decreases
Remain same
None of these
The power transmitted by belt drive depends upon
Belt velocity
Initial belt tension
Arc of contact
All of the above