In railway axle boxes, the bearing used is
Deep groove ball bearing
Double row self aligning ball bearing
Double row spherical roller bearing
Cylindrical roller bearing
Correct Answer :
C. Double row spherical roller bearing
Related Questions
The frequency of damped vibrations with viscous damping is ________ the frequency of undamped vibrations.
More than
Less than
Same as
None of these
The static friction
Bears a constant ratio to the normal reaction between the two surfaces
Is independent of the area of contact, between the two surfaces
Always acts in a direction, opposite to that in which the body tends to move
All of the above
To transmit power from one rotating shaft to another whose axes are neither parallel nor intersecting, use?
Spur gear
Spiral gear
Bevel gear
Worm gear
A cam with a roller follower would constitute following type of pair
Lower pair
Higher pair
Open pair
Close pair
When two links are connected by a pin joint, their instantaneous centre lies
On their point of contact
At the centre of curvature
At the centre of circle
At the pin joint
In a kinematic chain, a quaternary joint is equivalent to
One binary joint
Two binary joints
Three binary joints
Four binary joints
Efficiency of a screw jack is given by
tan (α + φ)/tanα
tanα/tan (α +φ)
tan (α - φ)/tanα
tanα/tan (α - φ)
The static balancing is satisfactory for low speed rotors but with increasing speeds, dynamic balancing becomes necessary. This is because, the
Unbalanced couples are caused only at higher speeds
Unbalanced forces are not dangerous at higher speeds
Effects of unbalances are proportional to the square of the speed
Effects of unbalances are directly proportional to the speed
Which of the following statement is wrong?
A round bar in a round hole form a turning pair
A square bar in a square hole form a sliding pair
A vertical shaft in a foot step bearing forms a successful constraint
All of the above
Which one of the following is an exact straight line mechanism using lower pairs?
Watts mechanism
Grasshopper mechanism
Roberts mechanism
Peaucelliers mechanism
The product of the diametral pitch and circular pitch is equal to
1
1/π
π
2 π
The gear train usually employed in clocks is a
Simple gear train
Reverted gear train
Sun and planet gear
Differential gear
The angle of inclination of the plane, at which the body begins to move down the plane is called
Angle of friction
Angle of repose
Angle of projection
None of these
When the relation between the controlling force (Fc) and radius of rotation (r) for a spring controlled governor is Fc = ar + b, then the governor will be
Stable
Unstable
Isochronous
None of these
When the sleeve of a Porter governor moves downwards, the governor speed
Increases
Decreases
Remain unaffected
First increases and then decreases
A Porter governor is a
Pendulum type governor
Dead weight governor
Spring loaded governor
Inertia governor
Which of the following is a lower pair?
Ball and socket i
Piston and cylinder
Cam and follower
Both (A) and (B) above
When the crank is at the inner dead centre, in a reciprocating steam engine, then the velocity of the piston will be
Minimum
Zero
Maximum
None of these
For an isochronous Hartnell governor (where r₁ and r₂ = Maximum and minimum radius of rotation of balls respectively, S₁ and S₂ = Maximum and minimum force exerted on the sleeve respectively, and M = Mass on the sleeve)
(m.g + S₁)/(m.g + S₂) = r₁/r₂
(m.g - S₁)/(m.g - S₂) = r₂/r₁
S₁/S₂ = r₁/r₂
S₂/S₁ = r₁/r₂
The mechanism forms a structure, when the number of degrees of freedom (n) is equal to
0
1
2
-1
The two links OA and OB are connected by a pin joint at O. If the link OA turns with angular velocity ω₁ rad/s in the clockwise direction and the link OB turns with angular velocity ω₂ rad/s in the clockwise direction, then the rubbing velocity at the pin joint O is (where r = Radius of the pin at O)
ω₁.ω₂.r
(ω₁ - ω₂)r
(ω₁ + ω₂)r
(ω₁ - ω₂)2r
The dynamic friction is the friction experienced by a body, when the body
Is in motion
Is at rest
Just begins to slide over the surface of the other body
None of the above
Torsional vibrations are said to occur when the particles of a body moves
Perpendicular to its axis
Parallel to its axis
In a circle about its axis
None of these
The motion between a pair which takes place in __________ is known as incompletely constrained motion.
One direction only
Two directions only
More than one direction
None of these
Which gear is used for connecting two coplanar and intersecting shafts?
Spur gear
Helical gear
Bevel gear
None of the above
Which gear train is used for higher velocity ratios in a small space?
Simple gear train
Compound gear train
Reverted gear train
Epicyclic gear train
A typewriter mechanism has 7 numbers of binary joints, six links and none of higher pairs. The mechanism is
Kinematically sound
Not sound
Soundness would depend upon which link is kept fixed
Data is not sufficient to determine same
Balancing of rotating and reciprocating parts of an engine is necessary when it runs at
Slow speed
Moderate speed
Highs peed
Any one of these
A kinematic chain requires at least
2 links and 3 turning pairs
3 links and 4 turning pairs
4 links and 4 turning pairs
5 links and 4 turning pairs
In a flat collar pivot bearing, the moment due to friction is proportional to
(r₁² - r₂²)/(r₁ - r₂)
(r₁² - r₂²)/(r₁ + r₂)
(r₁³ - r₂³)/(r₁² - r₂²)
(r₁³ - r₂³)/(r₁ - r₂)