In a Hartnell governor, the stiffness of the spring is given by (where S1 and S2 = Spring forces exerted on the sleeve at max. and min. radii of rotation, and h = Compression of the spring)
(S₁ + S₂)/h
(S₁ - S₂)/h
(S₁ + S₂)/2h
(S₁ - S₂)/2h
Correct Answer :
B. (S₁ - S₂)/h
Related Questions
In automobiles the power is transmitted from gear box to differential through
Bevel gear
Universal joint
Hooke's joint
Knuckle joint
The frictional torque transmitted in a flat pivot bearing, considering uniform wear, is (where μ = Coefficient of friction, W = Load over the bearing, and R = Radius of bearing surface)
(1/2) μ W R
(2/3) μ W R
(3/4) μ W R
μ W R
When the nature of contact between the elements of a pair is such that one element can turn about the other by screw threads, the pair is known as a
Screw pair
Spherical pair
Turning pair
Sliding pair
For an involute gear, the ratio of base circle radius and pitch circle radius is equal to
sinφ
cosφ
secφ
cosecφ
When a shaking force is transmitted through the springs, damping becomes detrimental when the ratio of its frequency to the natural frequency is greater than
0.25
0.5
1
2
The indicator using Watt mechanism is known as
Thompson indicator
Richard indicator
Simplex indicator
Thomson indicator
The ratio of the number of teeth to the pitch circle diameter in millimetres, is called
Circular pitch
Diametral pitch
Module
None of these
In a four bar chain or quadric cycle chain
Each of the four pairs is a turning pair
One is a turning pair and three are sliding pairs
Two are turning pairs and two are sliding pairs
Three are turning pairs and one is a sliding pair
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
When a slider moves on a fixed link having curved surface, their instantaneous centre lies
On their point of contact
At the centre of curvature
At the centre of circle
At the pin joint
The balancing weights are introduced in planes parallel to the plane of rotation of the disturbing mass. To obtain complete dynamic balance, the minimum number of balancing weights to be introduced in different planes is
1
2
3
4
In a system subjected to damped forced vibrations, the ratio of maximum displacement to the static deflection is known as
Critical damping ratio
Damping factor
Logarithmic decrement
Magnification factor
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 force due to revolving masses
Varies in magnitude but constant in direction
Varies in direction but constant in magnitude
Varies in magnitude and direction both
Constant in magnitude and direction both
Which one of the following is an exact straight line mechanism using lower pairs?
Watts mechanism
Grasshopper mechanism
Roberts mechanism
Peaucelliers mechanism
The included angle for the V-belt is usually
10° to 20°
20° to 30°
30° to 40°
60° to 80°
A rotor which is balanced statically but not dynamically is supported on two bearings L apart and at high speed of the rotor, reaction on the left bearing is R. The right side of the bearing is shifted to a new position 2L apart from the left bearing. At the same rotor speed, dynamic reaction on the left bearing in the new arrangement will
Remain same as before
Become equal to 2R
Become equal to R/2
Become equal to R/4
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
The maximum or minimum value of the swaying couple is
± c.m.ω².r
± a (1 - c) m.ω².r
± (a/√2) (1 - c) m.ω².r
± 2a (1 - c) m.ω².r
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 Coriolis component of acceleration acts
Along the sliding surface
Perpendicular to the sliding surface
At 45° to the sliding surface
Parallel to the sliding surface
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
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
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 gear having involute teeth, the normal to the involute is a tangent to the
Pitch circle
Base circle
Addendum circle
Dedendum circle
The gear train usually employed in clocks is a
Simple gear train
Reverted gear train
Sun and planet gear
Differential gear
Cross head and guides form a
Lower pair
Higher pair
Turning pair
Sliding pair
A mass of 1 kg is attached to the end of a spring with a stiffness of 0.7 N/mm. The critical damping coefficient of this system is
1.4 N-s/m
18.52 N-s/m
52.92 N-s/m
529.2 N-s/m
The steering of a ship means
Movement of a complete ship up and down in vertical plane about transverse axis
Turning of a complete ship in a curve towards right or left, while it moves forward
Rolling of a complete ship sideways
None of the above
The tendency of a body to resist change from rest or motion is known as
Mass
Friction
Inertia
Resisting force