If ω/ωn is very low for a body vibrating under steady state vibrations, the phase angle for all values of damping factors, will tend to approach
0°
90°
180°
360°
Correct Answer :
A. 0°
Related Questions
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
The Whitworth quick return motion mechanism is formed in a slider crank chain when the
Coupler link is fixed
Longest link is a fixed link
Slider is a fixed link
Smallest link is a fixed link
The ratio of maximum fluctuation of speed to the mean speed is called
Fluctuation of speed
Maximum fluctuation of speed
Coefficient of fluctuation of speed
None 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
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 minimum number of teeth on the pinion which will mesh with any gear without interference for 20° full depth involute teeth will be
12
14
18
24
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
In a Hartnell governor, if a spring of greater stiffness is used, then the governor will be
Less sensitive
More sensitive
Unaffected of sensitivity
Isochronous
If D₁ and D₂ be the diameters of driver and driven pulleys, then belt speed is proportional to
D₁/D₂
D₂/D₁
D₁.D₂
D₁
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
For the brake to be self locking, the force P at C shown in the below figure, should 
Be zero
Act in upward direction
Act in downward direction
None of these
The example of higher pair is
Belt, rope and chain drives
Gears, cams
Ball and roller bearings
All of the above
In an open pair, the two elements of a pair
Have a surface contact when in motion
Have a line or point contact when in motion
Are kept in contact by the action of external forces, when in motion
Are not held together mechanically
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
Which gear is used for connecting two coplanar and intersecting shafts?
Spur gear
Helical gear
Bevel gear
None of the above
If the rotating mass of a rim type flywheel is distributed on another rim type flywheel whose mean radius is half the mean radius of the former, then energy stored in the latter at the same speed will be
Four times the first one
Same as the first one
One fourth of the first one
One and a half times the first one
In a Hartnell governor, the lift of the sleeve is given by (where r₁ and r₂ = Max. and min. radii of rotation, x = Length of ball arm of the lever, and y = Length of sleeve arm of the lever)
(r₁ + r₂) (y/x)
(r₁ + r₂) (x/y)
(r₁ - r₂) (y/x)
(r₁ - r₂) (x/y)
The brake commonly used in railway trains is
Shoe brake
Band brake
Band and block brake
Internal expanding brake
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
Which of the following statements regarding laws governing the friction between dry surfaces are correct?
The friction force is dependent on the materials of the contact surfaces.
The friction force is directly proportional to the normal force.
The friction force is independent of me area of contact.
All of the above
Which one of the following is an exact straight line mechanism using lower pairs?
Watts mechanism
Grasshopper mechanism
Roberts mechanism
Peaucelliers mechanism
Tangential acceleration direction is
Along the angular velocity
Opposite to angular velocity
May be any one of these
Perpendicular to angular velocity
The natural frequency of free torsional vibrations of a shaft is equal to (where q = Torsional stiffness of the shaft, and I = Mass moment of inertia of the disc attached at the end of a shaft)
2π. √(q/I)
2π qI
(1/2π). √(q/I)
1/2π
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.
The partial balancing means
Balancing partially revolving masses
Balancing partially reciprocating masses
Best balancing of engines
All of these
In its simplest form, a cam mechanism consists of following number of links
1
2
3
4
The frictional torque transmitted in a truncated conical pivot bearing, considering uniform wear, is
(1/2). μ W cosec α (r₁ + r₂)
(2/3).μ W cosec α (r₁ + r₂)
(1/2). μ W cosec α [(r₁³ - r₂³)/(r₁² - r₂²)]
(2/3). μ W cosec α [(r₁³ - r₂³)/(r₁² - r₂²)]
If the damping factor for a vibrating system is unity, then the system will be
Over damped
Under damped
Critically damped
Without vibrations
Rectilinear motion of piston is converted into rotary by
Cross head
Slider crank
Connecting rod
Gudgeon pin
When the load on the engine increases, it becomes necessary to increase the supply of working fluid and when the load decreases, less working fluid is required. The supply of the working fluid to the engine is controlled by a
D-slide valve
Governor
Meyer's expansion valve
Flywheel