A key way lowers
The strength of the shaft
The rigidity of the shaft
Both the strength and rigidity of the shaft
The ductility of the shaft
Correct Answer :
C. Both the strength and rigidity of the shaft
Related Questions
In a transverse fillet welded joint, the size of weld is __________ the throat of weld.
0.5 times
Equal to
2 times
Double
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
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
A shaft is subjected to fluctuating loads for which the normal torque (T) and bending moment (M) are 1000 N-m and 500 N-m respectively. If the combined shock and fatigue factor for bending is 1.5 and combined shock and fatigue factor for torsion is 2, then the equivalent twisting moment for the shaft is
2000 N-m
2050 N-m
2100 N-m
2136 N-m
Aircraft body is usually fabricated by
Welding
Pre-casting
Riveting
Casting
Maximum principal stress theory is applicable for
Ductile materials
Brittle materials
Elastic materials
All of the above
In a multiple V-belt drive, when a single belt is damaged, it is preferable to change the complete set in order to
Reduce vibration
Reduce slip
Ensure uniform loading
Ensure proper alignment
Oldham coupling is used to connect two shafts
Which are perfectly aligned
Which are not in exact alignment
Which have lateral misalignment
Whose axes intersect at a small angle
A special case of ductility which permits materials to be rolled or hammered into thin sheets, is called
Plasticity
Elasticity
Ductility
Malleability
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 localised compressive stress at the area of contact between two members is known as
Bending stress
Shear stress
Tensile stress
Bearing stress
In the levers of first type, the mechanical advantage is __________ one.
Less than
Equal to
More than
None of these
The material generally used for aircraft components is
Mild steel
High speed steel
Stainless steel
Aluminium
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
Lewis form factor for 14 ½° composite and full depth involute system is (where T = Number of teeth)
0.124 - (0.684/T)
0.154 - (0.912/T)
0.175 - (0.841/T)
None of these
For a bevel gear having the pitch angle θ, the ratio of formative number of teeth (TE) to actual number of teeth (T) is
1/sinθ
1/cosθ
1/tanθ
sinθ cosθ
According to I.B.R., the distance between the rows of rivets, for equal number of rivets in more than one row for lap joint or butt joint (chain riveting) shall not be less than
d
1.5 d
2d
2.5 d
In a multiple V-belt drive, if one of the belts break, then
Only the broken belt is replaced
The entire set of belts is replaced
The broken belt and the belt on either side of it, is replaced
The broken belt need not to be replaced
A transmission shaft includes
Over head shaft
Counter shaft
Line shaft
All of these
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
The shock resistance of steel is increased by adding
Nickel
Chromium
Nickel and chromium
Cobalt and molybdenum
The endurance or fatigue limit is defined as the maximum value of the stress which a polished standard specimen can withstand without failure, for infinite number of cycles, when subjected to
Static load
Dynamic load
Static as well as dynamic load
Completely reversed load
In helical gears, the right hand helixes on one gear will mesh __________ helixes on the other gear.
Right hand
Left hand
Both A and B
None of these
Deep groove ball bearings are used for
Heavy thrust load only
Small angular displacement of shafts
Radial load at high speed
Combined thrust and radial loads at high speed
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
In most machine members, the damping capacity of the material should be
Low
Zero
High
Could be anything
When a belt drive is transmitting maximum power,
Effective tension is equal to centrifugal tension
Effective tension is half of centrifugal tension
Driving tension on slack side is equal to centrifugal tension
Driving tension on tight side is twice the centrifugal tension
Crowning on pulley helps
In decreasing the slip of the belt
In increasing the slip of the belt
To keep the belt in centre on a pulley while it is in motion
To increase pulley life
According to I.B.R., the efficiency of a triple riveted butt joint with double straps of unequal width (5 rivets per pitch length) should be
45 to 60 %
63 to 70 %
70 to 83 %
80 to 90 %
Which of the following is a permanent fastening?
Bolts
Keys
Cotters
Rivets