The frictional torque transmitted in a truncated conical pivot bearing, considering uniform pressure, is
(1/2). μ W cosecα (r₁ + r₂)
(2/3). μ W cosecα (r₁ + r₂)
(1/2). μ W cosecα [(r₁³ - r₂³)/(r₁² - r₂²)]
(2/3). μ W cosecα [(r₁³ - r₂³)/(r₁² - r₂²)]
Correct Answer :
D. (2/3). μ W cosecα [(r₁³ - r₂³)/(r₁² - r₂²)]
Related Questions
A shaft has two heavy rotors mounted on it. The transverse natural frequencies, considering each of the rotor separately, are 100 Hz and 200 Hz respectively. The lowest critical speed is
5,367 r.p.m.
6,000 r.p.m.
9,360 r.p.m.
12,000 r.p.m.
Instantaneous center of rotation of a link in a four bar mechanism lies on
Right side pivot of this link
Left side pivot of this link
A point obtained by intersection on extending adjoining links
Cant occur
A cam with a roller follower would constitute following type of pair
Lower pair
Higher pair
Open pair
Close pair
The dedendum circle diameter is equal to (where, φ = Pressure angle)
Pitch circle dia. × cosφ
Addendum circle dia. × cosφ
Clearance circle dia. × cosφ
Pitch circle dia. × sinφ
When there is a reduction in amplitude over every cycle of vibration, then the body is said to have
Free vibration
Forced vibration
Damped vibration
Under damped vibration
The swaying couple is due to the
Primary unbalanced force
Secondary unbalanced force
Two cylinders of locomotive
Partial balancing
A Porter governor is a
Pendulum type governor
Dead weight governor
Spring loaded governor
Inertia governor
In under damped vibrating system, the amplitude of vibration
Decreases linearly with time
Increases linearly with time
Decreases exponentially with time
Increases exponentially with time
The ratio of height of Porter governor (when length of arms and links are equal) to the height of Watt's governor is (where m = Mass of the ball, and M = Mass on the sleeve)
m/(m + M)
M/(m + M)
(m + M)/m
(m + M)/M
When a point at the end of a link moves with constant angular velocity, its acceleration will have
Radial component only
Tangential component only
Coriolis component only
Radial and tangential components both
Pitch point of a cam is
A point on the pitch curve having minimum pressure angle
A point on the pitch curve having maximum pressure angle
Any point on the pitch curve
Any point on the pitch circle
The gears are termed as medium velocity gears, if their peripheral velocity is
1-3 m/s
3-15 m/s
15-30 m/s
30-50 m/s
Oldham's coupling is the
Second inversion of double slider crank chain
Third inversion of double slider crank chain
Second inversion of single slider crank chain
Third inversion of slider crank chain
Rectangular bar in a rectangular hole is the following type of pair
Completely constrained motion
Partially constrained motion
Incompletely constrained motion
Freely constrained motion
The acceleration of a flat-faced follower when it has contact with the flank of a circular arc cam, is given by
ω² R cosθ
ω² (R - r₁) cosθ
ω² (R - r₁) sinθ
ω² r₁ sinθ
In considering friction of a V-thread, the virtual coefficient of friction (μ₁) is given by
μ₁ = μ sinβ
μ₁ = μ cosβ
μ₁ = μ/sinβ
μ₁ = μ/cosβ
The mechanism consisting of three turning pairs and one sliding pair, is called a
Single slider crank chain
Whitworth quick return motion mechanism
Crank and slotted lever quick return motion mechanism
All of the above
A machine mounted on a single coil spring has a period of free vibration of tp . If the spring is cut into four equal parts and placed in parallel and the machine is mounted on them, then the period of free vibration of the new system will become
tp /16
tp /4
4 tp
16 tp
In an ideal machine, the output as compared to input is
Less
More
Equal
May be less or more depending on efficiency
In multi V-belt transmission, if one of the belt is broken, we have to change the
Broken belt
Broken belt and its adjacent belts
All the belts
There is no need of changing any one as remaining belts can take care of transmission of load
An involute pinion and gear are in mesh. If both have the same size of addendum, then there will be an interference between the
Tip of the gear tooth and flank of pinion
Tip of the pinion and flank of gear
Flanks of both gear and pinion
Tip of both gear and pinion
Which of the following is a spring controlled governor?
Hartnell governor
Hartung governor
Wilson-Hartnell governor
All of these
A rotary internal combustion engine has __________ cylinders.
Four
Five
Six
Seven
A body in motion will be subjected to coriolis acceleration when that body is
In plane rotation with variable velocity
In plane translation with variable velocity
In plane motion which is a resultant of plane translation and rotation
Restrained to rotate while sliding over another body
The maximum frictional force, which comes into play, when a body just begins to slide over the surface of the other body, is known as
Static friction
Dynamic friction
Limiting friction
Coefficient of friction
When the body is suspended at the point of suspension, its periodic time and frequency will be ________ as compared to the body suspended at the point of percussion.
Same
Two times
Four times
None of these
When the two elements of a pair have a surface contact when relative motion takes place and the surface of one element slides over the surface of the other, the pair formed is known as a
Lower pair
Higher pair
Self-closed pair
Force-closed pair
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)
Angle of action of cam is defined as the angle
Of rotation of the cam for a definite displacement of the follower
Through which the cam rotates during the period in which the follower remains in the highest position
Moved by the cam from the instant the follower begins to rise, till it reaches its highest position
Moved by the cam from beginning of ascent to the termination of descent
Which of the following property of the instantaneous centre is correct?
A rigid link rotates instantaneously relative to another link at the instantaneous centre for the configuration of the mechanism considered.
The two rigid links have no linear velocity relative to each other at the instantaneous centre.
The velocity of the instantaneous centre relative to any third rigid link is same whether the instantaneous centre is regarded as a point on the first rigid link or on the second rigid link.
All of the above