While designing a screw in a screw jack against buckling failure, the end conditions for the screw are taken as
Both the ends fixed
Both the ends hinged
One end fixed and the other end hinged
One end fixed and the other end free
Correct Answer :
D. One end fixed and the other end free
Related Questions
The pitch of threads on a Jock nut in comparison to pitch of nut is
Same
Coarser
Finer
Very fine
The fatigue stress concentration factor is defined as
The ratio of endurance limit with stress concentration to the endurance limit without stress concentration
The ratio of endurance limit without stress concentration to the endurance limit with stress concentration
The product of the endurance limits with and without stress concentration
All of the above
The design of shafts made of brittle materials is based on
Guest's theory
Rankine's theory
St Venant's theory
Von Mises theory
According to Rankine's theory, the failure occurs at a point in a member
When the maximum shear stress in a biaxial stress system reaches the shear stress at elastic limit in a simple tension test
When the maximum principal stress in a biaxial stress system reaches the elastic limit of the material in a simple tension test
When the strain energy per unit volume in a biaxial stress system reaches the strain energy at the elastic limit per unit volume as determined from a simple tension test
When the maximum principal strain in a biaxial stress system reaches the strain at the elastic limit as determined from a simple tension test
The largest diameter of an external or internal screw thread is known as
Minor diameter
Major diameter
Pitch diameter
None of these
In designing a key, it is assumed that the distribution of forces along the length of key
Varies linearly
Is uniform throughout
Varies exponentially, being more at the torque-input end
Varies exponentially, being less at the torque-input end
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 smallest diameter of an external or internal screw thread is known as
Minor diameter
Major diameter
Pitch diameter
None of these
Stress concentration in cyclic loading is more serious in
Ductile materials
Brittle materials
Equally serious in both cases
Depends on other factors
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
A double strap butt joint (with equal straps) is
Always in single shear
Always in double shear
Either in single shear or double shear
Any one of these
In a partial journal bearing, the angle of contact of the bearing with the journal is
120°
180°
270°
360°
The speed of the sprocket reduces as the chain pitch __________ for a given number of teeth.
Increases
Decreases
Remain same
None of these
Ball bearing type screws are found in following application
Screw jack
Aeroplane engines
Crane
Steering mechanism
Taper usually provided on cotter is
1 in 5
1 in 10
1 in 24
1 in 40
The centre distance between two meshing involute gears is equal to
(Sum of base circle radii)/cosφ
(Difference of base circle radii)/cosφ
(Sum of pitch circle radii)/cosφ
(Difference of pitch circle radii)/cosφ
The designation M 33 × 2 of a bolt means
Metric threads of 33 numbers in 2 cm
Metric threads with cross-section of 33 mm
Metric threads of 33 mm outside diameter and 2 mm pitch
Bolt of 33 mm nominal diameter having 2 threads per cm
Coaxing is the procedure of increasing
Metal strength by cycling
Metal hardness by surface treatment
Metal resistance to corrosion by coating
Fatigue limit by overstressing the metal by successively increasing loadings
The centre to centre distance between two consecutive rivets in a row, is called
Margin
Pitch
Back pitch
Diagonal pitch
A bolt is designed on the basis of __________ with a large factor of safety.
Direct tensile stress
Direct compressive stress
Direct bending stress
Direct shear stress
Crushing resistance required to crush the rivet per pitch length is
p.d.σc
p.t.σc
n.d.t.σc
(p - d) t.σc
The property of a bearing material which has the ability to accomodate shaft deflections and bearing inaccuracies by plastic deformation without excessive wear and heating, is known as
Bondability
Embeddability
Comformability
Fatigue strength
The contact ratio is the ratio of
Length of arc of recess to the circular pitch
Length of path of contact to the circular pitch
Length of arc of contact to the circular pitch
Length of arc of approach to the circular pitch
In case of pressure vessels having closed ends, the fluid pressure induces
Longitudinal stress
Shear stress
Circumferential stress
None of these
Aircraft body is usually fabricated by
Welding
Pre-casting
Riveting
Casting
The objective of crowning of the flat pulleys of belt drive is to
Prevent the belt from running off the pulley
Increase the power transmission capacity
Increase the belt velocity
Prevent the belt joint from damaging the belt surface
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
According to Indian standard specifications, 100 H6/g5 means that
Tolerance grade for the hole is 6 and for the shaft is 5
Tolerance grade for the shaft is 6 and for the hole is 5
Tolerance grade for the shaft is 4 to 8 and for the hole is 3 to 7
Tolerance grade for the hole is 4 to 8 and for the shaft is 3 to 7
In a flat belt drive, if the slip between the driver and belt is 1 %, between the belt and follower is 3% and driver and follower pulley diameters are equal, then velocity ratio of the drive will be
0.96
0.97
0.98
0.99
The crest diameter of a screw thread is same as
Major diameter
Minor diameter
Pitch diameter
Core diameter