The transmissibility, for all values of damping factor, will be less than unity, if ω/ωn is
Equal to 1
Less than 2
Equal to 2
Greater than 2
Correct Answer :
D. Greater than 2
Related Questions
The acceleration of the reciprocating roller follower when it has contact with the straight flanks of the tangent cam, is given by
ω². (r₁ r₂). (1 - cos² θ)
ω². (r₁ + r₂). (1 + cos² θ)
ω². (r₁ + r₂). [(2 - cos² θ)/cos³ θ]
ω². (r₁ - r₂). (1 - sin² θ)
If the damping factor for a vibrating system is unity, then the system will be
Over damped
Under damped
Critically damped
Without vibrations
Which one of the following is an exact straight line mechanism using lower pairs?
Watts mechanism
Grasshopper mechanism
Roberts mechanism
Peaucelliers mechanism
Davis steering gear consists of
Sliding pairs
Turning pairs
Rolling pairs
Higher pairs
Which one of the following can completely balance several masses revolving in different planes on a shaft?
A single mass in different planes
Two masses in any two planes
A single mass in one of the planes of the revolving masses
Two equal masses in any two planes
The train value of a gear train is
Equal to velocity ratio of a gear train
Reciprocal of velocity ratio of a gear train
Always greater than unity
Always less than unity
The direction of linear velocity of any point on a link with respect to another point on the same link is
Parallel to the link joining the points
Perpendicular to the link joining the points
At 45° to the link joining the points
None of the above
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
A spring controlled governor is said to be isochronous when the controlling force
Increases as the radius of rotation decreases
Increases as the radius of rotation increases
Decreases as the radius of rotation increases
Remain constant for all radii of rotation
Scotch yoke mechanism is used to generate
Sine functions
Square roots
Logarithms
Inversions
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
The power transmitted by a belt is maximum when the maximum tension in the belt is _________ of centrifugal tension.
One-third
Two-third
Double
Three times
In a shaper mechanism, the Coriolis component of acceleration will
Not exist
Exist
Depend on position of crank
None of the above
In higher pair, the relative motion is
Purely turning
Purely sliding
Purely rotary
Combination of sliding and turning
The pressure angle of a cam depends upon
Offset between centre lines of cam and follower
Lift of follower
Angle of ascent
All of the above
Oldhams coupling is an inversion of the kinematic chain used in
Whitworth quick return mechanism
Elliptical trammels
Rotary engine
Universal joint
The pressure angle of a cam is the angle between the direction of the follower motion and a normal to the
Pitch circle
Base circle
Pitch curve
Prime circle
If the opposite links of a four bar linkage are equal, the links will always form a
Triangle
Rectangle
Parallelogram
Pentagon
The engine of an aeroplane rotates in clockwise direction when seen from the tail end and the aeroplane takes a turn to the left. The effect of gyroscopic couple on the aeroplane will be
To dip the nose and tail
To raise the nose and tail
To raise the nose and dip the tail
To dip the nose and raise the tail
For low and moderate speed engines, the cam follower should move with
Uniform velocity
Simple harmonic motion
Uniform acceleration and retardation
Cycloidal motion
The velocity of piston in a reciprocating steam engine is given by (where ω = Angular velocity of crank, r = Radius of crank pin circle, θ = Angle turned by crank from inner dead centre, and n = Ratio of length of connecting rod to the radius of crank)
ωr [sin θ + (sin 2θ/n)]
ωr [cos θ + (cos 2θ/n)]
ω²r [sin θ + (sin 2θ/n)]
ω²r [cos θ + (cos 2θ/n)]
When the relation between the controlling force (Fc) and radius of rotation (r) for a spring controlled governor is Fc = ar + b, then the governor will be
Stable
Unstable
Isochronous
None of these
The type of pair formed by two elements which are so connected that one is constrained to turn or revolve about a fixed axis of another element is known as
Turning pair
Rolling pair
Sliding pair
Spherical pair
When a point moves along a straight line, its acceleration will have
Radial component only
Tangential component only
Coriolis component only
Radial and tangential components both
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
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
A reed type tachometer use the principle of
Longitudinal vibration
Torsional vibration
Transverse vibration
Damped free vibration
For S.H.M. cam, the acceleration of the follower at the ends of the stroke and aimed stroke respectively, is
Maximum and zero
Zero and maximum
Minimum and maximum
Zero and minimum
The secondary unbalanced force is maximum __________ in one revolution of the crank.
Two times
Four times
Eight times
Sixteen times
The velocity of sliding of meshing gear teeth is (Where ω₁ and ω₂ are angular velocities of meshing gears and y is distance between point of contact and the pitch point)
(ω₁ + ω₂)y
(ω₁/ω₂)y
(ω₁ × ω₂)y
(ω₁ + ω₂)/y