The total number of instantaneous centres for a mechanism consisting of n links are
n/2
n
n - 1
n(n - 1)/2
Correct Answer :
D. n(n - 1)/2
Related Questions
The acceleration of a particle moving with simple harmonic motion, at any instant is given by
ωx
ω²x
ω²/x
ω³/x
The example of successfully constrained motion is a
Motion of an I.C. engine valve
Motion of the shaft between a footstep bearing
Piston reciprocating inside an engine cylinder
All of the above
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
The two links OA and OB are connected by a pin joint at O. If the link OA turns with angular velocity ω₁ rad/s in the clockwise direction and the link OB turns with angular velocity ω₂ rad/s in the clockwise direction, then the rubbing velocity at the pin joint O is (where r = Radius of the pin at O)
ω₁.ω₂.r
(ω₁ - ω₂)r
(ω₁ + ω₂)r
(ω₁ - ω₂)2r
The velocity of a body moving with simple harmonic motion is __________ at the mean position.
Zero
Minimum
Maximum
None of these
With usual notations for different parameters involved, the maximum fluctuations of energy for a flywheel is given by
2ECS
ECS/2
2ECS²
2E²CS
Which of the following statement is correct?
The primary unbalanced force is less than the secondary unbalanced force.
The primary unbalanced force is maximum twice in one revolution of the crank.
The unbalanced force due to reciprocating masses varies in magnitude and direction both.
The magnitude of swaying couple in locomotives is inversely proportional to the distance between the two cylinder centre lines
The gear train usually employed in clocks is a
Simple gear train
Reverted gear train
Sun and planet gear
Differential gear
The Klein's diagram is used when
Crank has uniform angular velocity
Crank has nonuniform angular velocity
Crank has uniform angular acceleration
Crank has nonuniform angular acceleration
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
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
Balancing of rotating and reciprocating parts of an engine is necessary when it runs at
Slow speed
Moderate speed
Highs peed
Any one of these
Ackermann steering gear consists of
Sliding pairs
Turning pairs
Rolling pairs
Higher pairs
The partial balancing of reciprocating parts in locomotives produces
Hammer blow
Swaying couple
Variation in tractive force along the line of stroke
All of the above
The power from the engine to the rear axle of an automobile is transmitted by means of
Worm and worm wheel
Spur gears
Bevel gears
Hooke's joint
Under logarithmic decrement, the amplitude of successive vibrations are
Constant
In arithmetic progression
In geometric progression
In logarithmic progression
Which gear is used for connecting two coplanar and intersecting shafts?
Spur gear
Helical gear
Bevel gear
None of the above
The balancing of a rigid rotor can be achieved by appropriately placing balancing masses in
A single plane
Two planes
Three planes
Four planes
Sense of tangential acceleration of a link
Is same as that of velocity
Is opposite to that of velocity
Could be either same or opposite to velocity
Is perpendicular to that of velocity
Angle of descent of cam is defined as the angle
During which the follower returns to its initial position
Of rotation of the cam for a definite displacement of the follower
Through which the cam rotates during the period in which the follower remains in the highest position
Moved by the cam from the instant the follower begins to rise, till it reaches its highest position
When the pitching of a ship is upward, the effect of gyroscopic couple acting on it will be
To move the ship towards starboard
To move the ship towards port side
To raise the bow and lower the stern
To raise the stern and lower the bow
The Bifilar suspension method is used to determine
Natural frequency of vibration
Position of balancing weights
Moment of inertia
Centripetal acceleration
A foot step bearing and rotor of a vertical turbine form examples of
Incompletely constrained motion
Partially constrained motion
Completely constrained motion
Successfully constrained motion
Which type of gearing is used in steering system of an automobile?
Rack and pinion
Worm and wheel
Spiral gears
None of the above
The static balancing is satisfactory for low speed rotors but with increasing speeds, dynamic balancing becomes necessary. This is because, the
Unbalanced couples are caused only at higher speeds
Unbalanced forces are not dangerous at higher speeds
Effects of unbalances are proportional to the square of the speed
Effects of unbalances are directly proportional to the speed
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
In a hydrodynamic journal bearing, there is
A very thin film of lubricant between the journal and the bearing such that there is contact between the journal and the bearing
A thick film of lubricant between the journal and the bearing
No lubricant between the journal and the bearing
A forced lubricant between the journal and the bearing
In a reciprocating steam engine, when the crank has turned from inner dead centre through an angle θ, the angular velocity of the connecting rod is given by
ω sinθ/(n² - sin²θ)1/2
ω cosθ/(n² - cos²θ)1/2
ω sinθ/(n² - cos²θ)1/2
ω cosθ/(n² - sin²θ)1/2
The equation of motion for a vibrating system with viscous damping is (d²x/dt²) + (c/m). (dx/dt) + (s/m). x = 0 If the roots of this equation are real, then the system will be
Over-damped
Under damped
Critically damped
Without vibrations
The Ackerman steering gear mechanism is preferred to the Davis steering gear mechanism, because
Whole of the mechanism in the Ackerman steering gear is on the back of the front wheels
The Ackerman steering gear consists of turning pairs
The Ackerman steering gear is most economical
Both (A) and (B)