The factor which affects the critical speed of a shaft is
Diameter of disc
Span of shaft
Eccentricity
All of these
Correct Answer :
D. All of these
Related Questions
The relation between number of links (l) and number of joints (j) in a kinematic chain is
l = (1/2).(j + 2)
l = (2/3).(j + 2)
l = (3/4).(j + 3)
l = j + 4
Two heavy rotating masses are connected by shafts of lengths l₁, l₂ and l₃ and the corresponding diameters are d₁, d₂ and d₃. This system is reduced to a torsionally equivalent system having uniform diameter d = d₁ of the shaft. The equivalent length of the shaft is
(l₁ + l₂ + l₃)/3
l = l₁ + l₂.(d₁/d₂)³ + l₂.(d₁/d₃)³
l = l₁ + l₂.(d₁/d₂)⁴ + l₃.(d₁/d₃)⁴
l₁ + l₂ + l₃
The cam follower generally used in aircraft engines is
Knife edge follower
Flat faced follower
Spherical faced follower
Roller follower
If the pressure angle is __________, a reciprocating follower will jam in its bearings.
Small
Too small
Large
Too large
Which one of the following is an exact straight line mechanism using lower pairs?
Watts mechanism
Grasshopper mechanism
Roberts mechanism
Peaucelliers mechanism
The dynamic friction is the friction experienced by a body, when the body
Is in motion
Is at rest
Just begins to slide over the surface of the other body
None of the above
Relationship between the number of links (L) and number of pairs (P) is
P = 2L - 4
P = 2L + 4
P = 2L + 2
P = 2L - 2
In Meyer's expansion valve, the main valve is driven by an eccentric having an angle of advance from
10°-15°
15°-25°
25°-30°
30°-40°
A shaft carrying three rotors will have
No node
One node
Two nodes
Three nodes
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)
Torsional vibrations are said to occur when the particles of a body moves
Perpendicular to its axis
Parallel to its axis
In a circle about its axis
None of these
When brakes are applied to all the four wheels of a moving car, the distance travelled by the car before it is brought to rest, will be
Maximum
Minimum
Zero
None of these
If the controlling force line for a spring controlled governor when produced intersects the Y-axis at the origin, then the governor is said to be
Stable
Unstable
Isochronous
None of these
The primary unbalanced force is maximum when the angle of inclination of the crank with the line of stroke is
0° and 90°
0° and 180°
90° and 180°
180° and 360°
The natural frequency of free longitudinal vibrations is equal to (where m = Mass of the body, s = Stiffness of the body, and δ = Static deflection of the body)
1/2π × √(s/m)
1/2π × √(g/δ)
0.4985/√δ
Any one of these
In a four-bar chain it is required to give an oscillatory motion to the follower for a continuous rotation of the crank. For the lengths of 50 mm of crank and 70 mm of the follower, determine theoretical maximum length of coupler. The minimum length of the coupler will be
45 mm
Slightly less than 45 mm
Slightly more than 45 mm
95 mm
Critical damping is a function of
Mass and stiffness
Mass and damping coefficient
Mass and natural frequency
Damping coefficient and natural frequency
The indicator using Watt mechanism is known as
Thompson indicator
Richard indicator
Simplex indicator
Thomson indicator
The secondary unbalanced force is __________ the primary unbalanced force.
One-half
Two-third
n times
1/n times
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)]
The number of centers in a crank driven slider crank mechanism is
0
2
4
6
At the nodal point in a shaft, the amplitude for torsional vibration will be
Minimum
Maximum
Zero
Infinity
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, if N coincides with O, then 
Acceleration and velocity of the piston P is zero
Acceleration and velocity of the piston P is maximum
Acceleration of the piston P is zero and its velocity is maximum
Acceleration of the piston P is maximum and its velocity is zero
The arrangement is called bevel gearing, when two __________ are connected by gears.
Intersecting and coplanar shafts
Nonintersecting and non-coplanar shafts
Parallel and coplanar shafts
Parallel and non-coplanar shafts
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 simple spring-mass vibrating system has a natural frequency of fn. If the spring stiffness is halved and the mass is doubled, then the natural frequency will become
fn/2
2 fn
4 fn
8 fn
A motor car moving at a certain speed takes a left turn in a curved path. If the engine rotates in the same direction as that of wheels, men due to centrifugal forc
The reaction on me inner wheels increases and on the outer wheels decreases
The reaction on the outer wheels increases and on the inner wheels decreases
The reaction on the front wheels increases and on the rear wheels decreases
The reaction on the rear wheels increases and on the front wheels decreases
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
In a flat collar pivot bearing, the moment due to friction is proportional to
(r₁² - r₂²)/(r₁ - r₂)
(r₁² - r₂²)/(r₁ + r₂)
(r₁³ - r₂³)/(r₁² - r₂²)
(r₁³ - r₂³)/(r₁ - r₂)
When two pulleys of different diameters are connected by means of an open belt, the angle of contact at the ________ pulley must be taken into consideration.
Smaller
Larger
Either A or B
None of these