The minimum number of teeth on the pinion which will mesh with any gear without interference for 20° full depth involute teeth will be
12
14
18
24
Correct Answer :
C. 18
Related Questions
For an isochronous Hartnell governor (where r₁ and r₂ = Maximum and minimum radius of rotation of balls respectively, S₁ and S₂ = Maximum and minimum force exerted on the sleeve respectively, and M = Mass on the sleeve)
(m.g + S₁)/(m.g + S₂) = r₁/r₂
(m.g - S₁)/(m.g - S₂) = r₂/r₁
S₁/S₂ = r₁/r₂
S₂/S₁ = r₁/r₂
A body of weight W is required to move up the rough inclined plane whose angle of inclination with the horizontal is α. The effort applied parallel to the plane is given by (where μ = tan φ = Coefficient of friction between the plane and the body)
P = W tan α
P = W tan (α + φ)
P = W (sin α + μ cos α)
P = W (cos α + μ sin α)
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
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
Which of the following is used to control the speed variations of the engine caused by the fluctuations of the engine turning moment?
D-slide valve
Governor
Flywheel
Meyer's expansion valve
When the primary direct crank of a reciprocating engine makes an angle of θ with the line of stroke, then the secondary direct crank will make an angle of _________ with the line of stroke.
θ/2
θ
2θ
4θ
The secondary unbalanced force is __________ the primary unbalanced force.
One-half
Two-third
n times
1/n times
In elliptical trammels
All four pairs are turning
Three pairs turning and one pair sliding
Two pairs turning and two pairs sliding
One pair turning and three pairs sliding
The two elements of a pair are said to form a higher pair, when they
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
Permit relative motion
Idler pulley is used
For changing the direction of motion of the belt
For applying tension
For increasing velocity ratio
All of the above
Angle of dwell of cam is defined as the angle
During which the follower returns to its initial position
Of rotation of the cam for definite displacement of the follower
Through which the cam rotates during the period in which the follower remains in the highest position
Moved by the cam from the instant the follower begins to rise, till it reaches its highest position
In a differential band brake as shown in the below figure, if the length OB is greater than OA, then the force P at C should act in the downward direction. 
Yes
No
Unpredictable
None of these
Torsional vibrations are said to occur when the particles of a body moves
Perpendicular to its axis
Parallel to its axis
In a circle about its axis
None of these
Transmission of power from the engine to the rear axle of an automobile is by means of
Compound gears
Worm and wheel method
Hooke's joint
Crown gear
The component of the acceleration, parallel to the velocity of the particle, at the given instant is called
Radial component
Tangential component
Coriolis component
None of these
When the pitching of a ship is __________ the effect of gyroscopic couple acting on it will be to move the ship towards port side.
Upward
Downward
Forward
Backward
When a rigid body is suspended vertically and it oscillates with a small amplitude under the action of the force of gravity, the body is known as
Simple pendulum
Compound pendulum
Torsional pendulum
Second's pendulum
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
A governor is said to be stable, if the
Radius of rotation of balls increases as the equilibrium speed decreases
Radius of rotation of balls decreases as the equilibrium speed decreases
Radius of rotation of balls increases as the equilibrium speed increases
Radius of rotation of balls decreases as the equilibrium speed increases
Creep in belt drive is due to
Weak material of the belt
Weak material of the pulley
Uneven extensions and contractions of the belt when it passes from tight side to slack side
Expansion of the belt
Sensitiveness of the governor is defined as the ratio of the
Mean speed to the maximum equilibrium speed
Mean speed to the minimum equilibrium speed
Difference of the maximum and minimum equilibrium speeds to the mean speed
Sum of the maximum and minimum equilibrium speeds to the mean speed
Two pulleys of radii r₁ and r₂ and at distance x apart are connected by means of an open belt drive. The length of the belt is
π (r₁ + r₂) + (r₁ + r₂)²/x + 2x
π (r₁ + r₂) + (r₁ - r₂)²/x + 2x
π (r₁ - r₂) + (r₁ - r₂)²/x + 2x
π (r₁ - r₂) + (r₁ + r₂)²/x + 2x
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
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%
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
When a point at the end of a link moves with constant angular velocity, its acceleration will have
Radial component only
Tangential component only
Coriolis component only
Radial and tangential components both
Which of the following statement is correct?
For constant velocity ratio transmission between two gears, the common normal at the point of contact must always pass through a fixed point on the line joining the centres of rotation of gears.
For involute gears, the pressure angle changes with the change in centre distance between gears.
The epicyclic gear trains involve rotation of atleast one gear axis about some other gear axis.
All of the above
With usual notations for different parameters involved, the maximum fluctuations of energy for a flywheel is given by
2ECS
ECS/2
2ECS²
2E²CS
The displacement of the reciprocating roller follower, when it has contact with the straight flanks of the tangent cam, is given by (where r₁ = Minimum radius of the cam, r₂ = Radius of the roller follower, and θ = Angle turned by the cam from the beginning of the follower displacement)
(r₁ - r₂) (1 - cosθ)
(r₁ + r₂) (1 + cosθ)
(r₁ - r₂) [(1 - cosθ)/cos θ]
(r₁ + r₂) [(1 - cosθ)/cos θ]
When a shaking force is transmitted through the springs, damping becomes detrimental when the ratio of its frequency to the natural frequency is greater than
0.25
0.5
1
2