The centrifugal tension in belts
Decreases the power transmitted
Increases the power transmitted
Increase the wrap angle
Increases the belt tension without increasing power transmission
Correct Answer :
D. Increases the belt tension without increasing power transmission
Related Questions
According to Unwin's formula, the relation between the diameter of rivet hole (d) and the thickness of plate (t) is given by (where d and t are in mm)
d = t
d = 1.6 t
d = 2t
d = 6t
A shaft is subjected to a maximum bending stress of 80 N/mm² and maximum shearing stress equal to 30 N/mm² at a particular section. If the yield point in tension of the material is 280 N/mm² and the maximum shear stress theory of failure is used, then the factor of safety obtained will be
2.5
2.8
3.0
3.5
When a closely coiled helical spring is subjected to a couple about its axis, the stress induced in the wire material of the spring is
Bending stress only
A combination of torsional shear stress and bending
Direct shear stress only
A combination of bending stress and direct shear stress
The included angle for the British Association thread is
29°
55°
47.3°
60°
The condition for maximum power transmission is that the maximum tension in the flat belt should be equal to
3 Pc
Pc
Pc/3
2 Pc Where, Pc = tension in belt due to centrifugal force
In order to have a connecting rod equally strong in buckling about X-axis and Y-axis, the moment of inertia about X-axis should be __________ the moment of inertia about Y-axis.
Equal to
Twice
Three times
Four times
Ball bearing type screws are found in following application
Screw jack
Aeroplane engines
Crane
Steering mechanism
In oilness bearings
The oil film pressure is generated only by the rotation of the journal
The oil film is maintained by supplying oil under pressure
Do not require external supply of lubricant
Grease required to be applied after some intervals
When a nut is tightened by placing a washer below it, the bolt will be subjected to following type of loads
Compression
Tension
Shear
Combined loads
When the fulcrum is in between the load and effort, the lever is said to be of
First type
Second type
Third type
Any one of these
When a helical compression spring is cut into halves, the stiffness of the resulting spring will be
Same
Double
One-half
One-fourth
In standard taper roller bearings, the angle of taper of outer raceway is
5°
8°
15°
25°
The belt slip occurs due to
Heavy load
Loose belt
Driving pulley too small
Any one of the above
The taper on cotter varies from
1 in 24 to 1 in 20
1 in 15 to 1 in 10
1 in 32 to 1 in 24
1 in 48 to 1 in 24
Aircraft body is usually fabricated by
Welding
Pre-casting
Riveting
Casting
The shock resistance of steel is increased by adding
Nickel
Chromium
Nickel and chromium
Cobalt and molybdenum
The helix angle for single helical gears ranges from
10° to 15°
15° to 20°
20° to 35°
35° to 50°
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
If an application calls for stresses on screw threads in one direction only, then the following type of thread would be best suited
Square
Acme
Buttress
BSW
A crankshaft is a __________ shaft.
Transmission
Machine
Machine frame
None of these
Yield point in fatigue loading as compared to static loading is
Same
Higher
Lower
Depends on other factors
In second type of levers,
Load is in between the fulcrum and effort
Effort is in between the fulcrum and load
Fulcrum is in between the load and effort
None of these
The resultant axial load on a bolt depends upon
External load applied
Initial tension due to tightening of the bolt
Relative elastic yielding of the bolt and the connected members
All of the above
Rankine's theory of failure is applicable for following type of materials
Brittle
Ductile
Elastic
Plastic
If P1 and P2 are the tight and slack side tensions in the belt, then the initial tension Pi (according to Barth) will be equal to
[(√P1 + √P2)/2]²
P1 + P2
2 × (P1 + P2)
[2 × (P1 + P2)] + Pc Where Pc is centrifugal tension
A plate with an elliptical hole in the centre, with semi-major axis (A) perpendicular to the direction of loading and semi-minor axis (b) along the direction of loading, is subjected to a pull P. The maximum stress induced at the edge of the hole is equal to (where σ = Stress for a plate with no hole i.e. nominal stress)
σ [1 + (b/2a)]
σ [1 + (2a/b)]
σ [1 + (b/3a)]
σ [1 + (3a/b)]
The material commonly used for crane hooks is
Cast iron
Wrought iron
Mild steel
Aluminium
The ratio of pitch circle diameter in millimetres to the number of teeth, is called
Circular pitch
Diametral pitch
Module
None of these
The elasticity is the property of a material which enables it to
Regains its original shape after deformation when the external forces are removed
Draw into wires by the application of a tensile force
Resists fracture due to high impact loads
Retain deformation produced under load permanently
The cross-section of the arm of a bell crank lever is
Rectangular
Elliptical
I-section
Any one of these