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4

The contact ratio is the ratio of

A. Length of pair of contact to the circular pitch

B. Length of arc of contact to the circular pitch

C. Length of arc of approach to the circular pitch

D. Length of arc of recess to the circular pitch

Correct Answer :

B. Length of arc of contact to the circular pitch


Related Questions

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4

The frictional torque transmitted in a conical pivot bearing, considering uniform pressure, is (where R = Radius of shaft, and α = Semi-angle of the cone)

A. (1/2) μ W R cosecα

B. (2/3) μ W R cosecα

C. (3/4) μ W R cosecα

D. μ W R cosecα

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4

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)

A. (ω₁ + ω₂)y

B. (ω₁/ω₂)y

C. (ω₁ × ω₂)y

D. (ω₁ + ω₂)/y

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4

In steady state forced vibrations, the amplitude of vibrations at resonance is __________ damping coefficient.

A. Equal to

B. Directly proportional to

C. Inversely proportional to

D. Independent of

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4

The frictional torque transmitted in a flat pivot bearing, assuming uniform wear, is (Where μ = Coefficient of friction, W=Load over the bearing, R=Radius of bearing)

A. μwr

B. ¾μWR

C. (2/3) μWR

D. ½μWR

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4

Which of the following is a lower pair?

A. Ball and socket i

B. Piston and cylinder

C. Cam and follower

D. Both (A) and (B) above

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4

Which type of gearing is used in steering system of an automobile?

A. Rack and pinion

B. Worm and wheel

C. Spiral gears

D. None of the above

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4

Angle of action of cam is defined as the angle

A. Of rotation of the cam for a definite displacement of the follower

B. Through which the cam rotates during the period in which the follower remains in the highest position

C. Moved by the cam from the instant the follower begins to rise, till it reaches its highest position

D. Moved by the cam from beginning of ascent to the termination of descent

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4

The contact ratio for gears is

A. Zero

B. Less than one

C. Greater than one

D. Infinity

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4

For simple harmonic motion of the of follower, a cosine curve represents

A. Displacement diagram

B. Velocity diagram

C. Acceleration diagram

D. All of the above

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4

Which of the following is a higher pair?

A. Belt and pulley

B. Turning pair

C. Screw pair

D. Sliding pair

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4

In a rigid link OA, velocity of A w.r.t. O will be

A. Parallel to OA

B. Perpendicular to OA

C. At 45° to OA

D. Along AO

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4

In vibration isolation system, if ω/ωn < 2, then for all values of damping factor, the transmissibility will be (where ω = Angular speed of the system, ωn = Natural frequency of vibration of the system)

A. Less than unity

B. Equal to unity

C. Greater than unity

D. Zero

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4

Which of the following statement is wrong?

A. The difference between the maximum and minimum energies is called maximum fluctuation of energy

B. The coefficient of fluctuation of speed is the ratio of maximum fluctuation of speed to the mean speed

C. The variations of energy above and below the mean resisting torque line is known as fluctuation of energy

D. None of the above

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4

The coriolis component of acceleration is taken into account for

A. Slider crank mechanism

B. Four bar chain mechanism

C. Quick return motion mechanism

D. All of these

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4

Which one of the following can completely balance several masses revolving in different planes on a shaft?

A. A single mass in different planes

B. Two masses in any two planes

C. A single mass in one of the planes of the revolving masses

D. Two equal masses in any two planes

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4

The cam follower generally used in automobile engines is

A. Knife edge follower

B. Flat faced follower

C. Spherical faced follower

D. Roller follower

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4

In vibration isolation system, the transmissibility will be equal to unity, for all values of damping factor, if ω/ωn is

A. Equal to 1

B. Equal to 2

C. Less than 2

D. Greater than 2

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4

For a kinematic chain to be considered as mechanism

A. Two links should be fixed

B. One link should be fixed

C. None of the links should be fixed

D. There is no such criterion

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4

A fixed gear having 200 teeth is in mesh with another gear having 50 teeth. The two gears are connected by an arm. The number of turns made by the smaller gear for one revolution of arm about the centre of bigger gear is

A. 2

B. 3

C. 4

D. 5

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4

In a simple harmonic motion, the velocity vector with respect to displacement vector

A. Is in phase

B. Leads by 90°

C. Leads by 180°

D. Lags by 90°

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4

In a steam engine, the earlier cut-off with a simple slide valve may be obtained by increasing the steam lap and the angle of advance of the eccentric but keeping constant the travel and lead of the valve, this method will

A. Cause withdrawing or throttling of steam

B. Reduce length of effective stroke of piston

C. Reduce maximum opening of port to steam

D. All of these

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4

Cross head and guides form a

A. Lower pair

B. Higher pair

C. Turning pair

D. Sliding pair

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4

In an ideal machine, the output as compared to input is

A. Less

B. More

C. Equal

D. May be less or more depending on efficiency

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4

In gears, interference takes place when

A. The tip of a tooth of a mating gear digs into the portion between base and root circles

B. Gears do not move smoothly in the absence of lubrication

C. Pitch of the gears is not same

D. Gear teeth are undercut

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4

Inertia force acts

A. Perpendicular to the acceleration force

B. Along the direction of acceleration force

C. Opposite to the direction of acceleration force

D. None of the above

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4

A fixed gear having 200 teeth is in mesh with another gear having 50 teeth. The two gears are connected by an arm. The number of turns made by the smaller gear for one revolution of arm about the centre of bigger gear is

A. 2

B. 4

C. 3

D. None of the above

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4

The sense of coriolis component 2 ωv is same as that of the relative velocity vector v rotated at

A. 45° in the direction of rotation of the link containing the path

B. 45° in the direction opposite to the rotation of the link containing the path

C. 90° in the direction of rotation of the link containing the path

D. 180° in the direction opposite to the rotation of the link containing the path

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4

A disturbing mass m₁ attached to the rotating shaft may be balanced by a single mass m₂ attached in the same plane of rotation as that of m₁, such that (where r₁ and r₂ are the radii of rotation of m₁ and m₂ respectively)

A. m₁r₂ = m₂r₁

B. m₁r₁ = m₂r₂

C. m₁m₂ = r₁r₂

D. None of these

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4

The two parallel and coplanar shafts are connected by gears having teeth parallel to the axis of the shaft. This arrangement is known as

A. Spur gearing

B. Helical gearing

C. Bevel gearing

D. Spiral gearing

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4

A single degree of freedom system is given by, m × (d²x/dt²) + c × (dx/dt) + sx = F.cosω.t with usual notations. It represents

A. Free vibration with damping

B. Free vibration without damping

C. Forced vibration with damping

D. Forced vibration without damping