The constant factor in case of R10 series of preferred numbers is
1.06
1.12
1.26
1.58
Correct Answer :
C. 1.26
Related Questions
In hydrostatic 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 is used for lubrication
The form factor of a helical gear __________ with the increase in the helix angle.
Increases
Decreases
Remains constant
None of these
When the screw in a mechanical screw jack rotates, the load kept on the top of it moves
Axially upwards
Axially downwards
Axially upwards or downwards
None of these
A spring of stiffness 1000 N/m is stretched initially by 100 mm from the undeformed position. The work required to stretch it by another 100 mm is
5 N-m
7 N-m
10 N-m
15 N-m
In nitrated parts, the origins of the fatigue cracks will occur at
Surface
Just below the surface
Within the core
None of the above
A key made from a cylindrical disc having segmental cross-section, is known as
Woodruff key
Feather key
Flat saddle key
Gib head key
In designing a connecting rod, it is considered like __________ for buckling about Y-axis.
Both ends hinged
Both ends fixed
One end fixed and the other end hinged
One end fixed and the other end free
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
A screw is said to be a self locking screw, if its efficiency is
Less than 50 %
More than 50 %
Equal to 50 %
None of these
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
The circumferential and longitudinal strains in a cylindrical boiler under internal steam pressure are εc and εl respectively. The change in volume of the boiler cylinder per unit volume will be
εc + 2εl
2εc + εl
εc + εl²
εc² + εl
Lewis equation in gears is used to find the
Tensile stress in bending
Shear stress
Compressive stress in bending
Fatigue stress
Two rigid plates are clamped by means of bolt and nut with an initial force F. After tightening, a separating force P (P < F) is applied to the lower plate, which in turn acts on the nut. The tension in the both after this is
F + P
F P
P
F
In replacing the V-belts, a complete set of new belts is used instead of replacing a single damaged belt because
Belts are available in sets
Only one belt cannot be fitted with other used belts
The new belt will carry more than its share and result in short life
New and old belts will cause vibrations
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 relation between the pitch of the chain (p) and pitch circle diameter of the sprocket (D) is given by (where T = Number of teeth on the sprocket)
p = D sin (90°/T)
p = D sin (120°/T)
p = D sin (180°/T)
p = D sin (360°/T)
An open belt drive is used when
Shafts are arranged at right angles and rotate in one definite direction
Shafts are arranged parallel and rotate in the opposite directions
Shafts are arranged parallel and rotate in the same directions
Driven shaft is to be started or stopped whenever desired without interfering with the driving shaft
In radial cams, the follower moves
In a direction parallel to the cam axis
In a direction perpendicular to the cam axis
In any direction irrespective of cam axis
Along the cam axis
The value of Lewis form factor used in design of gears is
Dependent on number of teeth of a gear
Dependent on system of teeth
Independent of size of teeth
All of these
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
The strength of a riveted joint is equal to
Tearing strength of plate (Pt)
Shearing strength of rivet (Ps)
Crushing strength of rivet (Pc)
Least value of Pt Ps and Pc
Which one of the following is a positive drive?
V-belt drive
Rope drive
Crossed flat belt drive
Chain drive
Which of the following spring is used in mechanical wrist watch?
Helical compression spring
Spiral spring
Torsion spring
Belleville spring
A locking device extensively used in marine type connecting rod ends is a
Jam nut
Castle nut
Sawn nut
Ring nut
In cross or regular lay ropes
Direction of twist of wires in strands is opposite to the direction of twist of strands
Direction of twist of wires and strands are same
Wires in two adjacent strands are twisted in opposite direction
Wires are not twisted
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
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
A connecting rod is designed as a
Long column
Short column
Strut
All of these
Two closely coiled helical springs with stiffness k₁ and k₂ respectively are connected in series. The stiffness of an equivalent spring is given by
(k₁ k₂)/ (k₁ + k₂)
(k₁ - k₂)/ (k₁ + k₂)
(k₁ + k₂)/ (k₁ k₂)
(k₁ - k₂)/ (k₁ k₂)
A special case of ductility which permits materials to be rolled or hammered into thin sheets, is called
Plasticity
Elasticity
Ductility
Malleability