The two elements of a pair are said to form a _________ when they permit relative motion between them.
Open pair
Kinematic pair
Sliding pair
None of these
Correct Answer :
B. Kinematic pair
Related Questions
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.
The tractive force in a locomotive with two cylinders is given by (where c = Fraction of reciprocating parts per cylinder, m = Mass of reciprocating parts, ω = Angular speed of crank, r = Radius of crank, and θ = Angle of inclination of crank to the line of stroke)
m.ω².r cosθ
c.m.ω².r sinθ
(1 - c).m.ω².r (cosθ - sinθ)
m.ω².r (cosθ - sinθ)
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
Which of the following is false statement in respect of differences between machine and structure?
Machines transmit mechanical work, whereas structures transmit forces
In machines, relative motion exists between its members, whereas same does not exist in case of structures
Machines modify movement and work, whereas structures modify forces
Efficiency of machines as well as structures is below 100%
Efficiency of a screw jack is given by
tan (α + φ)/tanα
tanα/tan (α +φ)
tan (α - φ)/tanα
tanα/tan (α - φ)
A kinematic chain requires at least
2 links and 3 turning pairs
3 links and 4 turning pairs
4 links and 4 turning pairs
5 links and 4 turning pairs
A spring controlled governor is said to be unstable 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
Remains constant for all radii of rotation
In a radial cam, the follower moves
In a direction perpendicular to the cam axis
In a direction parallel to the cam axis
In any direction irrespective of the cam axis
Along the cam axis
The stress induced in a body will be shear stress, when it is subjected to
Longitudinal vibrations
Transverse vibrations
Torsional vibrations
None of these
Peaucelliers mechanism has
Eight links
Six links
Four links
Twelve links
Klein's construction gives a graphic construction for
Slider-crank mechanism
Velocity polygon
Acceleration polygon
Four bar chain mechanism
A circle passing through the pitch point with its center at the center of cam axis is known as
Pitch circle
Base circle
Prime circle
Outer circle
For simple harmonic motion of the of follower, a cosine curve represents
Displacement diagram
Velocity diagram
Acceleration diagram
All of the above
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)
To obviate axial thrust, following gear drive is used
Double helical gears having opposite teeth
Double helical gears having identical teeth
Single helical gear in which one of the teeth of helix angle a is more
Mutter gears
The two elements of a pair are said to form a _________ when they permit relative motion between them.
Open pair
Kinematic pair
Sliding pair
None of these
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
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 rotating shafts tend to vibrate violently at whirling speeds because
The system is unbalanced
Bearing centre line coincides with the axis
The shafts are rotating at very high speeds
Resonance is caused due to the heavy mass of the rotor
In a steam engine, the distance by which the outer edge of the Dslide valve overlaps the steam port is called
Lead
Steam lap
Exhaust lap
None of these
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 the equation are __________ then the system will be under damped.
Equal
Real
Complex conjugate
None of these
A shaft has two heavy rotors mounted on it. The transverse natural frequencies, considering each of the rotor separately, are 100 Hz and 200 Hz respectively. The lowest critical speed is
5,367 r.p.m.
6,000 r.p.m.
9,360 r.p.m.
12,000 r.p.m.
In railway axle boxes, the bearing used is
Deep groove ball bearing
Double row self aligning ball bearing
Double row spherical roller bearing
Cylindrical roller bearing
In gramophones for adjusting the speed of the turntable, the following type of governor is commonly employed
Hartung governor
Wilson Hartnell governor
Pickering governor
Inertia governor
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
The number of links in pantograph mechanism is equal to
2
3
4
5
Ball and a Socket forms a
Turning pair
Rolling pair
Screw pair
Spherical pair
Coriolis component is encountered in
Quick return mechanism of shaper
Four bar chain mechanism
Slider crank mechanism
Both (A) and (C) above
In a gear having involute teeth, the normal to the involute is a tangent to the
Pitch circle
Base circle
Addendum circle
Dedendum circle
The mechanism consisting of three turning pairs and one sliding pair, is called a
Single slider crank chain
Whitworth quick return motion mechanism
Crank and slotted lever quick return motion mechanism
All of the above