A pantograph is a mechanism with
Lower pairs
Higher pairs
Rolling pairs
Turning pairs
Correct Answer :
A. Lower pairs
Related Questions
Which of the following disciplines provides study of inertia forces arising from the combined effect of the mass and the motion of the parts?
Theory of machines
Applied mechanics
Mechanisms
Kinetics
If two moving elements have surface contact in motion, such pair is known as
Sliding pair
Rolling pair
Surface pair
Higher pair
Klein's construction gives a graphic construction for
Slider-crank mechanism
Velocity polygon
Acceleration polygon
Four bar chain mechanism
In S.H.M., the velocity vector w.r.t. displacement vector
Leads by 90°
Lags by 90°
Leads by 180°
Are in phase
Whitworth quick return mechanism is obtained by inversion of
Slider crank mechanism
Kinematic chain
Five link mechanism
Roller cam mechanism
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 distance between fixed pivots of crank and followers is
95 mm
Slightly less than 95 mm
Slightly more than 95 mm
45 mm
For a twin cylinder V-engine, the crank positions for primary reverse cranks and secondary direct cranks are shown in the below figure. The engine is a 
30° V-engine
60° V-engine
120° V-engine
150° V-engine
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.
The example of lower pair is
Shaft revolving in a bearing
Straight line motion mechanisms
Automobile steering gear
All of the above
The radial distance from the top of a tooth to the bottom of a tooth in a meshing gear, is called
Dedendum
Addendum
Clearance
Working depth
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
The instantaneous centres which vary with the configuration of mechanism are called
Permanent instantaneous centres
Fixed instantaneous centres
Neither fixed nor permanent instantaneous centres
None of the above
In a steam engine, one method of obtaining the earlier cut-off with a simple slide valve is by increasing the angle of advance of the eccentric while the throw of the eccentric, steam lap and exhaust lap are kept constant. This method will
Cause withdrawing or throttling of steam
Reduce length of effective stroke of piston
Reduce maximum opening of port to steam
All of these
The acceleration of a particle moving with simple harmonic motion, at any instant is given by
ωx
ω²x
ω²/x
ω³/x
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
The frictional torque transmitted in a flat pivot bearing with assumption of uniform pressure is _________ as compared to uniform wear.
Less
More
Same
None of these
The method of direct and reverse cranks is used in engines for
The control of speed fluctuations
Balancing of forces and couples
Kinematic analysis
Vibration analysis
In a simple train of wheels, the velocity ratio __________ the intermediate wheels.
Depends upon
Is independent of
Either A or B
None of these
The centre of gravity of a coupler link in a four bar mechanism will experience
No acceleration
Only linear acceleration
Only angular acceleration
Both linear and angular acceleration
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°
Ball and a Socket forms a
Turning pair
Rolling pair
Screw pair
Spherical pair
When a slider moves on a fixed link having curved surface, their instantaneous centre lies
On their point of contact
At the centre of curvature
At the centre of circle
At the pin joint
The number of links in pantograph mechanism is equal to
2
3
4
5
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 pair is known as a higher pair, when the relative motion between the elements of a pair is
Turning only
Sliding only
Rolling only
Partly turning and partly sliding
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
In S.H.M., acceleration is proportional to
Velocity
Displacement
Rate of change of velocity
All of the above
If ω/ωn = 2, where co is the frequency of excitation and ωn is the natural frequency of vibrations, then the transmissibility of vibration will the
0.5
1
1.5
2
For high speed engines, the cam follower should move with
Uniform velocity
Simple harmonic motion
Uniform acceleration and retardation
Cycloidal motion
The motion between a pair when limited to a definite direction, irrespective of the direction of force applied, is known as
Completely constrained motion
Incompletely constrained motion
Successfully constrained motion
None of these