The number of links in pantograph mechanism is equal to
2
3
4
5
Correct Answer :
C. 4
Related Questions
When the axes of the first and last wheels are coaxial, then the train is known as
Simple train of wheels
Compound train of wheels
Reverted gear train
Epicyclic gear train
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)
The purpose of a link is to
Transmit motion
Guide other links
Act as a support
All of the above
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
A flywheel is fitted to the crankshaft of an engine having W as the amount of indicated work per revolution and permissible limits of coefficient of fluctuation of energy and speed as CE and CS respectively. The kinetic energy of the flywheel is given by
2 W CE / CS
W CE / 2CS
W CE / CS
W CS / 2CE
A point B on a rigid link AB moves with respect to A with angular velocity ω rad/s. The radial component of the acceleration of B with respect to A, is (where vBA = Linear velocity of B with respect to A)
vBA × AB
vBA /AB
v²BA
v²BA /AB
In steady state forced vibrations, the amplitude of vibrations at resonance is __________ damping coefficient.
Equal to
Directly proportional to
Inversely proportional to
Independent of
The velocity of sliding of meshing gear teeth is (Where ω₁ and ω₂ are angular velocities of meshing gears and y is distance between point of contact and the pitch point)
(ω₁ + ω₂)y
(ω₁/ω₂)y
(ω₁ × ω₂)y
(ω₁ + ω₂)/y
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 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°
In a Hartnell governor, the compression of the spring is __________ the lift of the sleeve.
Equal to
Less than
Greater than
None of these
The cam follower generally used in aircraft engines is
Knife edge follower
Flat faced follower
Spherical faced follower
Roller follower
A reed type tachometer use the principle of
Longitudinal vibration
Torsional vibration
Transverse vibration
Damped free vibration
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
When a ship travels in a sea, which of the effect is more dangerous
Steering
Pitching
Rolling
All of the above
The sensitiveness of the governor __________ as the speed range decreases.
Remains unaffected
Decreases
Increases
None of these
Klein's construction is useful to determine
Velocity of various parts
Acceleration of various parts
Displacement of various parts
Angular acceleration of various parts
The frequency of oscillation of a compound pendulum is
2π. √[gh/(kG² + h²)]
2π. √[(kG² + h²)/gh]
(1/2π). √[gh/(kG² + h²)]
(1/2π). √[(kG² + h²)/gh]
The maximum velocity of a particle moving with simple harmonic motion is
ω
ωr
ω²r
ω/r
The critical speed of a shaft in revolution per second is __________ as that of natural frequency of transverse vibration.
Same
Different
Unpredictable
None of these
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
Pulley in a belt drive acts as
Cylindrical pair
Turning pair
Rolling pair
Sliding pair
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
An involute pinion and gear are in mesh. If both have the same size of addendum, then there will be an interference between the
Tip of the gear tooth and flank of pinion
Tip of the pinion and flank of gear
Flanks of both gear and pinion
Tip of both gear and pinion
Which of the following governor is used to drive a gramophone?
Watt governor
Porter governor
Pickering governor
Hartnell governor
The equivalent length of a simple pendulum which gives the same frequency as a compound pendulum is
h/(kG² + h²)
(kG² + h²)/h
h²/(kG² + h²)
(kG² + h²)/h²
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.
Which of the following statement is correct as regard to the difference between a machine and a structure?
The parts of a machine move relative to one another, whereas the members of a structure do not move relative to one another
The links of a machine may transmit both power and motion, whereas the members of a structure transmit forces only
A machine transforms the available energy into some useful work, whereas in a structure no energy is transformed into useful work
All of the above
When the elements of a pair are kept in contact by the action of external forces, the pair is said to be a
Lower pair
Higher pair
Self-closed pair
Force-closed pair