The frictional torque transmitted in a flat collar bearing, considering uniform wear, is (where r₁ and r₂ = External and internal radii of collar respectively)
(1/2) μ W (r₁ + r₂)
(2/3) μ W (r₁ + r₂)
(1/2) μ W [(r₁³ - r₂³)/(r₁² - r₂²)]
(2/3) μ W [(r₁³ - r₂³)/(r₁² - r₂²)]
Correct Answer :
A. (1/2) μ W (r₁ + r₂)
Related Questions
In locomotives, the ratio of the connecting rod length to me crank radius is kept very large in order to
Minimise the effect of primary forces
Minimise the effect of secondary forces
Have perfect balancing
To start the locomotive quickly
The example of rolling pair is
Bolt and nut
Lead screw of a lathe
Ball and socket joint
Ball bearing and roller bearing
The ratio of the driving tensions for V-belts is __________ times that of flat belts. (Where β = Semi-angle of the groove)
sinβ
cosβ
cosecβ
secβ
In a turning moment diagram, the variations of energy above and below the mean resisting torque line is called
Fluctuation of energy
Maximum fluctuation of energy
Coefficient of fluctuation of energy
None of these
In a reciprocating engine, usually __________ of the reciprocating masses are balanced.
One-half
Two-third
Three-fourth
Whole
For an involute gear, the ratio of base circle radius and pitch circle radius is equal to
sinφ
cosφ
secφ
cosecφ
When the pitching of a ship is __________ the effect of gyroscopic couple acting on it will be to move the ship towards port side.
Upward
Downward
Forward
Backward
The ratio of maximum fluctuation of speed to the mean speed is called
Fluctuation of speed
Maximum fluctuation of speed
Coefficient of fluctuation of speed
None of these
The displacement of the reciprocating roller follower, when it has contact with the straight flanks of the tangent cam, is given by (where r₁ = Minimum radius of the cam, r₂ = Radius of the roller follower, and θ = Angle turned by the cam from the beginning of the follower displacement)
(r₁ - r₂) (1 - cosθ)
(r₁ + r₂) (1 + cosθ)
(r₁ - r₂) [(1 - cosθ)/cos θ]
(r₁ + r₂) [(1 - cosθ)/cos θ]
Which of the following statement is correct for gears?
The addendum is less than the dedendum
The pitch circle diameter is the product of module and number of teeth
The contact ratio means the number of pairs of teeth in contact
All of the above
The example of completely constrained motion is a
Motion of a piston in the cylinder of a steam engine
Motion of a square bar in a square hole
Motion of a shaft with collars at each end in a circular hole
All of the above
In gramophones for adjusting the speed of the turntable, the following type of governor is commonly employed
Hartung governor
Wilson Hartnell governor
Pickering governor
Inertia governor
The moment on the pulley which produces rotation is called
Inertia
Momentum
Moment of momentum
Torque
In a steam engine, the link constitutes a
Piston, piston rod and crosshead
Connecting rod with big and small end brasses, caps and bolts
Crank pin, crankshaft and flywheel
All of the above
When the sleeve of a Porter governor moves downwards, the governor speed
Increases
Decreases
Remain unaffected
First increases and then decreases
When the two elements of a pair have __________ when in motion, it is said to a lower pair.
Line or point contact
Surface contact
Body contact
None of these
Coriolis component acts
Perpendicular to sliding surfaces
Along sliding surfaces
Somewhere in between above two
None of the above
The type of coupling used to join two shafts whose axes are neither in same straight line nor parallel, but intersect is
Flexible coupling
Universal coupling
Chain coupling
Oldham's coupling
The equation of motion for a vibrating system with viscous damping is (d²x/dt²) + (c/m). (dx/dt) + (s/m). x = 0 If the roots of this equation are real, then the system will be
Over-damped
Under damped
Critically damped
Without vibrations
In involute gears, the pressure angle is
Dependent on the size of teeth
Dependent on the size of gears
Always constant
Always variable
The Klein's method of construction for reciprocating engine mechanism
Is a simplified version of instantaneous centre method
Utilises a quadrilateral similar to the diagram of mechanism for reciprocating engine
Enables determination of coriolis component
Is based on the acceleration diagram
The power of a Porter governor is equal to
[c²/(1 + 2c)] (m + M) g.h
[2c²/(1 + 2c)] (m + M) g.h
[3c²/(1 + 2c)] (m + M) g.h
[4c²/(1 + 2c)] (m + M) g.h
Sensitiveness of the governor is defined as the ratio of the
Mean speed to the maximum equilibrium speed
Mean speed to the minimum equilibrium speed
Difference of the maximum and minimum equilibrium speeds to the mean speed
Sum of the maximum and minimum equilibrium speeds to the mean speed
The length of a simple pendulum which gives the same frequency as the compound pendulum, is
kG + l₁
kG² + l₁
(kG² + l₁²)/ l₁
(kG + l₁²)/ l₁
The essential condition of placing the two masses, so that the system becomes dynamically equivalent, is (where l₁ and l₂ = Distance of two masses from the centre of gravity of the body, and kG = Radius of gyration of the body)
l₁ = kG
l₂ = kG
l₁l₂ = kG
l₁l₂ = kG²
In higher pair, the relative motion is
Purely turning
Purely sliding
Purely rotary
Combination of sliding and turning
In a rigid link OA, velocity of A w.r.t. O will be
Parallel to OA
Perpendicular to OA
At 45° to OA
Along AO
The equation of motion for a single degree of freedom system with viscous damping is 4(dx²/dt²) + 9(dx/dt) + 16x. The damping ratio of the system is
9/8
9/82
9/16
9/128
The size of a gear is usually specified by
Pressure angle
Circular pitch
Diametral pitch
Pitch circle diameter
The C.G. of a link in any mechanism would experience
No acceleration
Linear acceleration
Angular acceleration
Both angular and linear accelerations