The frequency of damped vibrations with viscous damping is ________ the frequency of undamped vibrations.
More than
Less than
Same as
None of these
Correct Answer :
B. Less than
Related Questions
A shaft has an attached disc at the centre of its length. The disc has its centre of gravity located at a distance of 2 mm from the axis of the shaft. When the shaft is allowed to vibrate in its natural bow-shaped mode, it has a frequency of vibration of 10 rad/s. When the shaft is rotated at 300 r.p.m., it will whirl with a radius of
2 mm
2.22 mm
2.50 mm
3.0 mm
Transmission angle is the angle between
Input link and coupler
Input link and fixed link
Output link and coupler
Output link and fixed link
A body is said to be under forced vibrations, when
There is a reduction in amplitude after every cycle of vibration
No external force acts on a body, after giving it an initial displacement
A body vibrates under the influence of external force
None of the above
The frictional torque transmitted in a flat collar bearing, considering uniform pressure, is (where r₁ and r₂ = External and internal radii of collar respectively)
(1/2). μ W (r₁ + r₂)
(2/3). μ W (r₁ + r₂)
(1/2). μ W [(r₁³ - r₂³)/(r₁² - r₂²)]
(2/3). μ W [(r₁³ - r₂³)/(r₁² - r₂²)]
In the below figure, PC is the connecting rod and OC is the crank making an angle θ with the line of stroke PO and rotates with uniform angular velocity at ω rad/s. The Klien's acceleration diagram for determining the acceleration of the piston P is shown by quadrilateral CQNO. The acceleration of the piston P with respect to the crankpin C is given by 
ω² × NO
ω² × CO
ω² × CN
ω² × QN
To connect two parallel and coplanar shafts the following type of gearing is used
Spur gear
Bevel gear
Spiral gear
None of the above
The displacement of the reciprocating roller follower, when it has contact with the straight flanks of the tangent cam, is given by (where r₁ = Minimum radius of the cam, r₂ = Radius of the roller follower, and θ = Angle turned by the cam from the beginning of the follower displacement)
(r₁ - r₂) (1 - cosθ)
(r₁ + r₂) (1 + cosθ)
(r₁ - r₂) [(1 - cosθ)/cos θ]
(r₁ + r₂) [(1 - cosθ)/cos θ]
Which of the following has sliding motion?
Crank
Connecting rod
Crank pin
Crosshead
Shaft revolving in a bearing is the following type of pair
Lower pair
Higher pair
Spherical pair
Cylindrical pair
The maximum efficiency of spiral gears is (where θ = Shaft angle, and φ = Friction angle)
sin (θ + φ) + 1/ cos (θ - φ) + 1
cos (θ - φ) + 1/ sin (θ + φ) + 1
cos (θ + φ) + 1/ cos (θ - φ) + 1
cos (θ - φ) + 1/ cos (θ + φ) + 1
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
If some links are connected such that motion between them can take place in more than one direction, it is called
Incompletely constrained motion
Partially constrained motion
Completely constrained motion
Successfully constrained motion
Which of the following statement is correct for involute gears?
The interference is inherently absent.
The variation in centre distance of shafts increases radial force.
A convex flank is always in contact with concave flank.
The pressure angle is constant throughout the teeth engagement.
Which of the following statement is correct?
The periodic time of a particle moving with simple harmonic motion is the time taken by a particle for one complete oscillation.
The periodic time of a particle moving with simple harmonic motion is directly proportional to its angular velocity.
The velocity of a particle moving with simple harmonic motion is zero at the mean position.
The acceleration of the particle moving with simple harmonic motion is maximum at the mean position.
When the radius of rotation of balls __________ as the equilibrium speed increases, the governor is said to be unstable.
Remains constant
Decreases
Increases
None of these
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
Rectilinear motion of piston is converted into rotary by
Cross head
Slider crank
Connecting rod
Gudgeon pin
The moment on the pulley which produces rotation is called
Inertia
Momentum
Moment of momentum
Torque
Which of the following disciplines provides study of inertia forces arising from the combined effect of the mass and the motion of the parts?
Theory of machines
Applied mechanics
Mechanisms
Kinetics
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
Maximum fluctuation of energy in a flywheel is equal to [where I = Mass moment of inertia of the flywheel, E = Maximum fluctuation of energy, CS = Coefficient of fluctuation of speed, and ω = Mean angular speed = (ω₁ + ω₂)/2]
I.ω.(ω₁ - ω₂)
I.ω².CS
2.E.CS
All of these
Which of the following disciplines provides study of relative motion between the parts of a machine?
Theory of machines
Applied mechanics
Mechanisms
Kinematics
When the pitching of a ship is __________ the effect of gyroscopic couple acting on it will be to move the ship towards port side.
Upward
Downward
Forward
Backward
A watt's governor can work satisfactorily at speeds from
60 to 80 r.p.m.
80 to 100 r.p.m.
100 to 200 r.p.m.
200 to 300 r.p.m.
In elliptical trammels
All four pairs are turning
Three pairs turning and one pair sliding
Two pairs turning and two pairs sliding
One pair turning and three pairs sliding
Cross head and guides form a
Lower pair
Higher pair
Turning pair
Sliding pair
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
In a circular arc cam with roller follower, the acceleration in any position of the lift will depend only upon
Total lift, total angle of lift, minimum radius of cam and cam speed
Radius of circular arc, cam speed, location of centre of circular arc and roller diameter
Mass of cam follower linkage, spring stiffness and cam speed
Total lift, centre of gravity of the cam and cam speed
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
In S.H.M., acceleration is proportional to
Velocity
Displacement
Rate of change of velocity
All of the above