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4

Minimum number of teeth for involute rack and pinion arrangement for pressure angle of 20° is

A. 18

B. 20

C. 30

D. 34

Correct Answer :

A. 18


Related Questions

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4

An involute pinion and gear are in mesh. If both have the same size of addendum, then there will be an interference between the

A. Tip of the gear tooth and flank of pinion

B. Tip of the pinion and flank of gear

C. Flanks of both gear and pinion

D. Tip of both gear and pinion

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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

There are six gears A, B, C, D, E and F in a compound train. The numbers of teeth in the gears are 20, 60, 30, 80, 25 and 75 respectively. The ratio of angular speeds of the driven (F) to the driver (A) of the drive is

A. 1/24

B. 1/8

C. 4/15

D. 12

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4

In a flat collar pivot bearing, the moment due to friction is proportional to

A. (r₁² - r₂²)/(r₁ - r₂)

B. (r₁² - r₂²)/(r₁ + r₂)

C. (r₁³ - r₂³)/(r₁² - r₂²)

D. (r₁³ - r₂³)/(r₁ - r₂)

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4

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

A.

B. 90°

C. 180°

D. 360°

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4

In a coupling rod of a locomotive, each of the four pairs is a ________ pair.

A. Sliding

B. Turning

C. Rolling

D. Screw

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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

Which of the following property of the instantaneous centre is correct?

A. A rigid link rotates instantaneously relative to another link at the instantaneous centre for the configuration of the mechanism considered.

B. The two rigid links have no linear velocity relative to each other at the instantaneous centre.

C. The velocity of the instantaneous centre relative to any third rigid link is same whether the instantaneous centre is regarded as a point on the first rigid link or on the second rigid link.

D. All of the above

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4

Effort of a governor is the

A. Mean force exerted at the sleeve for a given percentage change of speed

B. Workdone at the sleeve for maximum equilibrium speed

C. Mean force exerted at the sleeve for maximum equilibrium speed

D. None of the above

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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

Which of the following is an open pair?

A. Journal bearing

B. Ball and Socket joint

C. Leave screw and nut

D. None of the above

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4

The locus of a point on a thread unwound from a cylinder will be

A. A straight line

B. A circle

C. Involute

D. Cycloidal

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4

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

A. (1/2) μ W R

B. (2/3) μ W R

C. (3/4) μ W R

D. μ W R

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4

The indicator using Watt mechanism is known as

A. Thompson indicator

B. Richard indicator

C. Simplex indicator

D. Thomson indicator

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4

The number of links in pantograph mechanism is equal to

A. 2

B. 3

C. 4

D. 5

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4

Rectilinear motion of piston is converted into rotary by

A. Cross head

B. Slider crank

C. Connecting rod

D. Gudgeon pin

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4

For fluctuating loads, well suited bearing is

A. Ball bearing

B. Roller bearing

C. Needle roller bearing

D. Thrust bearing

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4

The instantaneous centre of a rigid thin disc rolling on a plane rigid surface is located at

A. The centre of the disc

B. The point of contact

C. An infinite distance on the plane surface

D. The point on the circumference situated vertically opposite to the contact point

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4

The stress induced in a body will be shear stress, when it is subjected to

A. Longitudinal vibrations

B. Transverse vibrations

C. Torsional vibrations

D. None of these

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4

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)

A. 1/2π × √(s/m)

B. 1/2π × √(g/δ)

C. 0.4985/√δ

D. Any one of these

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4

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)

A. ω √(x² - r²)

B. ω √(r² - x²)

C. ω² √(x² - r²)

D. ω² √(r² - x²)

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4

The pressure angle of a cam is the angle between the direction of the follower motion and a normal to the

A. Pitch circle

B. Base circle

C. Pitch curve

D. Prime circle

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4

The swaying couple is maximum or minimum when the angle of inclination of the crank to the line of stroke (θ) is equal to

A. 90° and 180°

B. 45° and 225°

C. 180° and 270°

D. 270° and 360°

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4

A combination of kinematic pairs, joined in such a way that the relative motion between the links is completely constrained, is called a

A. Structure

B. Mechanism

C. Kinematic chain

D. Inversion

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4

Two systems shall be dynamically equivalent when

A. The mass of two are same

B. C.G. of two coincides

C. M.I. of two about an axis through e.g. is equal

D. All of the above

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4

The coriolis component of acceleration depends upon

A. Velocity of slider

B. Angular velocity of the link

C. Both (A) and (B)

D. None of these

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4

The velocity of a flat-faced follower when it has contact with the flank of a circular arc cam, is given by

A. ωR cosθ

B. ω(R - r₁) cosθ

C. ω(R - r₁) sinθ

D. ωr₁ sinθ

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4

In a reciprocating engine, usually __________ of the reciprocating masses are balanced.

A. One-half

B. Two-third

C. Three-fourth

D. Whole

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4

When the belt is stationary, it is subjected to some tension known as initial tension. The value of this tension is equal to the

A. Tension in the tight side of the belt

B. Tension in the slack side of the belt

C. Sum of the tensions on the tight side and slack side of the belt

D. Average tension of the tight side and slack side of the belt

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4

A mechanism is an assemblage of

A. Two links

B. Three links

C. Four or more than four links

D. All of these