In an open pair, the two elements of a pair
Have a surface contact when in motion
Have a line or point contact when in motion
Are kept in contact by the action of external forces, when in motion
Are not held together mechanically
Correct Answer :
D. Are not held together mechanically
Related Questions
The flank of the tooth is the surface of the tooth __________ the pitch surface.
Above
Below
At
None of these
Which of the following is an inversion of a single slider crank chain?
Pendulum pump
Oscillating cylinder engine
Rotary internal combustion engine
All of these
Relationship between the number of links (L) and number of pairs (P) is
P = 2L - 4
P = 2L + 4
P = 2L + 2
P = 2L - 2
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
The displacement of a flat faced follower when it has contact with the flank of a circular arc cam, is given by (where R = Radius of flank, r₁ = Minimum radius of the cam, and θ = Angle turned through by the cam)
R (1 - cosθ)
(R - r₁) (1 - cosθ)
R (1 - sinθ)
(R - r₁) (1 - sinθ)
In a screw jack, the effort required to lower the load W is given by
P = W tan(α - φ)
P = W tan(α + φ)
P = W tan(φ - α)
P = W cos(α + φ)
When a mass of a critically damped single degree of freedom system is deflected from its equilibrium position and released, then it will
Return to equilibrium position without oscillation
Oscillate with increasing time period
Oscillate with decreasing amplitude
Oscillate with constant amplitude
A motor car moving at a certain speed takes a left turn in a curved path. If the engine rotates in the same direction as that of wheels, men due to centrifugal forc
The reaction on me inner wheels increases and on the outer wheels decreases
The reaction on the outer wheels increases and on the inner wheels decreases
The reaction on the front wheels increases and on the rear wheels decreases
The reaction on the rear wheels increases and on the front wheels decreases
Ball and a Socket forms a
Turning pair
Rolling pair
Screw pair
Spherical pair
A slider crank chain consists of following numbers of turning and sliding pairs
1, 3
2, 2
3, 1
4, 0
In a multiple V-belt drive, when a single belt is damaged, it is preferable to change the complete set to
Reduce vibration
Reduce slip
Ensure uniform loading
Ensure proper alignment
Which of the following is a turning pair?
Piston and cylinder of a reciprocating steam engine
Shaft with collars at both ends fitted into a circular hole
Lead screw of a lathe with nut
Ball and a socket joint
The maximum value of the pressure angle in case of cam is kept as
10°
14°
20°
30°
The natural frequency of free transverse vibrations due to a point load acting over a simply supported shaft is equal to (where δ = Static deflection of a simply supported shaft due to the point load)
0.4985/√δ
0.5615/√δ
0.571/√δ
0.6253/√δ
The cam follower generally used in automobile engines is
Knife edge follower
Flat faced follower
Spherical faced follower
Roller follower
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 component of the acceleration, perpendicular to the velocity of the particle, at the given instant is called
Radial component
Tangential component
Coriolis component
None of these
When the two elements of a pair have __________ when in motion, it is said to a lower pair.
Line or point contact
Surface contact
Body contact
None of these
A single degree of freedom system is given by, m × (d²x/dt²) + c × (dx/dt) + sx = F.cosω.t with usual notations. It represents
Free vibration with damping
Free vibration without damping
Forced vibration with damping
Forced vibration without damping
A shaft has an attached disc at the centre of its length. The disc has its centre of gravity located at a distance of 2 mm from the axis of the shaft. When the shaft is allowed to vibrate in its natural bow-shaped mode, it has a frequency of vibration of 10 rad/s. When the shaft is rotated at 300 r.p.m., it will whirl with a radius of
2 mm
2.22 mm
2.50 mm
3.0 mm
The size of cam depends upon
Base circle
Pitch circle
Prime circle
Pitch curve
For dynamic balancing of a shaft
The net dynamic force acting on the shaft is equal to zero
The net couple due to the dynamic forces acting on the shaft is equal to zero
Both (A) and (B)
None of the above
When the particles of a body moves perpendicular to its axis, then the body is said to have
Longitudinal vibration
Transverse vibration
Torsional vibration
None of these
The working depth of a gear is the radial distance from the
Pitch circle to the bottom of a tooth
Pitch circle to the top of a tooth
Top of a tooth to the bottom of a tooth
Addendum circle to the clearance circle
The absolute acceleration of any point P in a link about center of rotation O is
Along PO
Perpendicular to PO
At 45° to PO
None of the above
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
The partial balancing means
Balancing partially revolving masses
Balancing partially reciprocating masses
Best balancing of engines
All of these
The tractive force is maximum or minimum when the angle of inclination of crank with the line of stroke (θ) is equal to
0° and 90°
90° and 180°
135° and 315°
270° and 360°
In S.H.M., acceleration is proportional to
Velocity
Displacement
Rate of change of velocity
All of the above
When a body moves with simple harmonic motion, the product of its periodic time and frequency is equal to
Zero
One
π/2
π