A spring controlled governor is found unstable. It can be made stable by
Increasing the spring stiffness
Decreasing the spring stiffness
Increasing the ball mass
Decreasing the ball mass
Correct Answer :
B. Decreasing the spring stiffness
Related Questions
A flywheel is fitted to the crankshaft of an engine having W as the amount of indicated work per revolution and permissible limits of coefficient of fluctuation of energy and speed as CE and CS respectively. The kinetic energy of the flywheel is given by
2 W CE / CS
W CE / 2CS
W CE / CS
W CS / 2CE
If the damping factor for a vibrating system is unity, then the system will be
Over damped
Under damped
Critically damped
Without vibrations
The frequency of oscillation of a torsional pendulum is
2πk/r. √(g/l)
r/2πk. √(l/g)
2πr/k. √(g/l)
r/2πk. √(g/l)
When the nature of contact between the elements of a pair is such that it can only slide relative to the other, the pair is known as a
Screw pair
Spherical pair
Turning pair
Sliding pair
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
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
A body will begin to move down an inclined plane, if the angle of inclination of the plane is ________ the angle of friction.
Equal to
Less than
Greater than
None of these
A system of masses rotating in different parallel planes is in dynamic balance if the
Resultant force is equal to zero
Resultant couple is equal to zero
Resultant force and resultant couple are both equal to zero
Resultant force is numerically equal to the resultant couple, but neither of them need necessarily be zero
The unbalanced force due to reciprocating 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
A fixed gear having 200 teeth is in mesh with another gear having 50 teeth. The two gears are connected by an arm. The number of turns made by the smaller gear for one revolution of arm about the centre of bigger gear is
2
3
4
5
The gear train usually employed in clocks is a
Simple gear train
Reverted gear train
Sun and planet gear
Differential gear
A point B on a rigid link AB moves with respect to A with angular velocity ω rad/s. The radial component of the acceleration of B with respect to A, is (where vBA = Linear velocity of B with respect to A)
vBA × AB
vBA /AB
v²BA
v²BA /AB
The acceleration of the particle moving with simple harmonic motion is _________ at the mean position.
Zero
Minimum
Maximum
None of these
The fundamental equation for correct steering is (where φ and α = Angle through which the axis of the outer wheel and inner wheel turns respectively, c = Distance between the pivots of the front axles, and d = Wheel base)
sinφ + sinα = b/c
cosφ - sinα = c/b
cotφ - cotα = c/b
tanφ + cotα = b/c
The indicator using Watt mechanism is known as
Thompson indicator
Richard indicator
Simplex indicator
Thomson indicator
A Hartnell governor has its controlling force (Fc) given by Fc = ar + b, where r is the radius of rotation and a and b are constants. The governor becomes isochronous when
a is +ve and b = 0
a = 0 and b is +ve
a is +ve and b is -ve
a is +ve and b is also +ve
Effort of a governor is the
Mean force exerted at the sleeve for a given percentage change of speed
Workdone at the sleeve for maximum equilibrium speed
Mean force exerted at the sleeve for maximum equilibrium speed
None of the above
A cam with a roller follower would constitute following type of pair
Lower pair
Higher pair
Open pair
Close pair
Which of the following governor is used to drive a gramophone?
Watt governor
Porter governor
Pickering governor
Hartnell governor
The swaying couple is maximum or minimum when the angle of inclination of the crank to the line of stroke (θ) is equal to
90° and 180°
45° and 225°
180° and 270°
270° and 360°
The secondary unbalanced force due to inertia of reciprocating parts in a reciprocating engine is given by (where m = Mass of reciprocating parts, ω = Angular speed of crank, r = Radius of crank, θ = Angle of inclination of crank with the line of stroke, and n = Ratio of the length of connecting rod to radius of crank)
m.ω².r sinθ
m.ω².r cosθ
m.ω².r (sin 2θ/n)
m.ω².r (cos 2θ/n)
The equation of free vibrations of a system is (d²x/dt²) +36 π²x, its natural frequency is
3 Hz
3π Hz
6 Hz
6π Hz
Which gear is used for connecting two coplanar and intersecting shafts?
Spur gear
Helical gear
Bevel gear
None of the above
The lead screw of a lathe with nut forms a
Rolling pair
Sliding pair
Screw pair
Turning pair
In a locomotive, the resultant unbalanced force due to the two cylinders along the line of stroke, is known as
Tractive force
Swaying couple
Hammer blow
None of these
In a reciprocating steam engine, which of the following forms a kinematic link?
Cylinder and piston
Piston rod and connecting rod
Crankshaft and flywheel
Flywheel and engine frame
It is required to connect two parallel shafts, the distance between whose axes is small and variable. The shafts are coupled by
Universal joint
Knuckle joint
Oldham's coupling
Flexible coupling
A higher pair has__________.
Point contact
Surface contact
No contact
None of the above
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
A pulley and belt in a belt drive form a
Cylindrical pair
Turning pair
Rolling pair
Sliding pair