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
Correct Answer :
D. All of the above
Related Questions
If the radius of gyration of a compound pendulum about an axis through e.g. is more, then its frequency of oscillation will be
Less
More
Same
Data are insufficient to determine same
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 driving and driven shafts connected by a Hooke's joint will have equal speeds, if
cosθ = sinα
sinθ = ± tanα
tanθ = ± cosα
cotθ = cosα
In Meyer's expansion valve, the expansion valve is driven by an eccentric having an angle of advance from
50°-60°
60°-70°
70°-80°
80°-90°
What is the number of instantaneous centres for an eight link mechanism?
15
28
30
8
The example of higher pair is
Belt, rope and chain drives
Gears, cams
Ball and roller bearings
All of the above
Which of the following is a spring controlled governor?
Hartnell governor
Hartung governor
Wilson-Hartnell governor
All of these
In vibration isolation system, the transmissibility will be equal to unity, for all values of damping factor, if ω/ωn is
Equal to 1
Equal to 2
Less than 2
Greater than 2
The flank of the tooth is the surface of the tooth __________ the pitch surface.
Above
Below
At
None of these
In a steam engine, the link constitutes a
Piston, piston rod and crosshead
Connecting rod with big and small end brasses, caps and bolts
Crank pin, crankshaft and flywheel
All of the above
The velocity of a particle moving with simple harmonic motion, at any instant is given by (where ω = Displacement of the particle from mean position)
ω √(x² - r²)
ω √(r² - x²)
ω² √(x² - r²)
ω² √(r² - x²)
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 the rotating mass of a rim type flywheel is distributed on another rim type flywheel whose mean radius is half the mean radius of the former, then energy stored in the latter at the same speed will be
Four times the first one
Same as the first one
One fourth of the first one
One and a half times the first one
A chain comprises of 5 links having 5 joints. Is it kinematic chain?
Yes
No
It is a marginal case
Data are insufficient to determine it
The Klein's method of construction for reciprocating engine mechanism
Is based on acceleration diagram
Is a simplified form of instantaneous center method
Utilises a quadrilateral similar to the diagram of mechanism for reciprocating engine
Enables determination of Carioles component
Kinematic pairs are those which have
Two elements held together mechanically
Two elements having relative motion
Two elements having Coriolis component
Minimum of two instantaneous centres
3.The retardation of a flat faced follower when it has contact at the apex of the nose of a circular arc cam, is given by (where OQ = Distance between the centre of circular flank and centre of nose)
ω² × OQ
ω² × OQ sinθ
ω² × OQ cosθ
ω² × OQ tanθ
When the relation between the controlling force (Fc) and radius of rotation (r) for a spring controlled governor is Fc = ar + b, then the governor will be
Stable
Unstable
Isochronous
None of these
In a reciprocating engine, usually __________ of the reciprocating masses are balanced.
One-half
Two-third
Three-fourth
Whole
In gears, interference takes place when
The tip of a tooth of a mating gear digs into the portion between base and root circles
Gears do not move smoothly in the absence of lubrication
Pitch of the gears is not same
Gear teeth are undercut
The contact ratio is given by
(Length of the path of approach)/(Circular pitch)
(Length of path of recess)/(Circular pitch)
(Length of the arc of contact)/(Circular pitch)
(Length of the arc of approach)/cosφ
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
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 sensitiveness of the governor __________ as the speed range decreases.
Remains unaffected
Decreases
Increases
None of these
The danger of breakage and vibration is maximum
Below the critical speed
Near the critical speed
Above the critical speed
None of these
Crowning on pulleys helps
In increasing velocity ratio
In decreasing the slip of the belt
For automatic adjustment of belt position so that belt runs centrally
Increase belt and pulley life
The frequency of damped vibrations with viscous damping is ________ the frequency of undamped vibrations.
More than
Less than
Same as
None of these
A mechanism is an assemblage of
Two links
Three links
Four or more than four links
All of these
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
The acceleration of a particle at any instant has two components i.e. radial component and tangential component. These two components will be
Parallel to each other
Perpendicular to each other
Inclined at 45°
Opposite to each other