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
Correct Answer :
C. (m + M)/m
Related Questions
The advantage of the piston valve over the slide valve is that in the former case
Wear is less
Power absorbed is less
Both wear and power absorbed are low
The pressure developed being high provides tight sealing
A pantograph is a mechanism with
Lower pairs
Higher pairs
Rolling pairs
Turning pairs
The total number of instantaneous centres for a mechanism consisting of n links are
n/2
n
n - 1
n(n - 1)/2
The sensitiveness of the governor __________ as the speed range decreases.
Remains unaffected
Decreases
Increases
None of these
In order to double the period of a simple pendulum, the length of the string should be
Halved
Doubled
Quadrupled
None of these
The tractive force is maximum or minimum when the angle of inclination of crank with the line of stroke (θ) is equal to
0° and 90°
90° and 180°
135° and 315°
270° and 360°
For the same lift and same angle of ascent, a smaller base circle will give
A small value of pressure angle
A large value of pressure angle
There is no such relation with pressure angle
Something else
If the number of links in a mechanism is equal to l, then the numbers of possible inversions are equal to
l - 2
l - 1
l
l + 1
Open pairs are those which have
Point or line contact between the two elements when in motion
Surface contact between the two elements when in motion
Elements of pairs not held together mechanically
Two elements that permit relative motion
The maximum fluctuation of speed is the
Difference of minimum fluctuation of speed and the mean speed
Difference of the maximum and minimum speeds
Sum of maximum and minimum speeds
Variations of speed above and below the mean resisting torque line
The balancing of a rigid rotor can be achieved by appropriately placing balancing masses in
A single plane
Two planes
Three planes
Four planes
The mechanism in which two are turning pairs and two are sliding pairs, is called a
Double slider crank chain
Elliptical trammel
Scotch yoke mechanism
All of these
An exact straight line motion mechanism is a
Scott-Russell's mechanism
Hart's mechanism
Peaucellier's mechanism
All of these
In a multiple V-belt drive, when a single belt is damaged, it is preferable to change the complete set to
Reduce vibration
Reduce slip
Ensure uniform loading
Ensure proper alignment
The component of the acceleration, parallel to the velocity of the particle, at the given instant is called
Radial component
Tangential component
Coriolis component
None of these
In a disc clutch, if there are n₁ number of discs on the driving shaft and n₂ number of discs on the driven shaft, then the number of pairs of contact surfaces will be
n₁ + n₂
n₁ + n₂ + 1
n₁ + n₂ - 1
n₁ + n₂ - 2
To obviate axial thrust, following gear drive is used
Double helical gears having opposite teeth
Double helical gears having identical teeth
Single helical gear in which one of the teeth of helix angle a is more
Mutter gears
The unbalanced primary forces in a reciprocating engine are
Balanced completely
Balanced partially
Balanced by secondary forces
Not balanced
Which of the following statement is correct as regard to the difference between a machine and a structure?
The parts of a machine move relative to one another, whereas the members of a structure do not move relative to one another
The links of a machine may transmit both power and motion, whereas the members of a structure transmit forces only
A machine transforms the available energy into some useful work, whereas in a structure no energy is transformed into useful work
All of the above
Module of a gear is
D/T
T/D
2D/T
2T/D
The factor which affects the critical speed of a shaft is
Diameter of disc
Span of shaft
Eccentricity
All of these
When the particles of a body moves perpendicular to its axis, then the body is said to have
Longitudinal vibration
Transverse vibration
Torsional vibration
None of these
There are six gears A, B, C, D, E and F in a compound train. The numbers of teeth in the gears are 20, 60, 30, 80, 25 and 75 respectively. The ratio of angular speeds of the driven (F) to the driver (A) of the drive is
1/24
1/8
4/15
12
The example of higher pair is
Belt, rope and chain drives
Gears, cams
Ball and roller bearings
All of the above
The maximum efficiency of a screw jack is
(1 - sinφ)/(1 + sinφ)
(1 + sinφ)/(1 - sinφ)
(1 - tanφ)/(1 + tanφ)
(1 + tanφ)/(1 - tanφ)
Frequency of vibrations is usually expressed in
Number of cycles per hour
Number of cycles per minute
Number of cycles per second
None of these
The example of lower pair is
Shaft revolving in a bearing
Straight line motion mechanisms
Automobile steering gear
All of the above
The Scott-Russell mechanism consists of
Sliding and turning pairs
Sliding and rotary pairs
Turning and rotary pairs
Sliding pairs only
The frictional torque transmitted in a flat pivot bearing, assuming uniform wear, is (Where μ = Coefficient of friction, W=Load over the bearing, R=Radius of bearing)
μwr
¾μWR
(2/3) μWR
½μWR
The size of a gear is usually specified by
Pressure angle
Circular pitch
Diametral pitch
Pitch circle diameter