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4

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)

A. (m.g + S₁)/(m.g + S₂) = r₁/r₂

B. (m.g - S₁)/(m.g - S₂) = r₂/r₁

C. S₁/S₂ = r₁/r₂

D. S₂/S₁ = r₁/r₂

Correct Answer :

A. (m.g + S₁)/(m.g + S₂) = r₁/r₂


Related Questions

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4

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)

A. (r₁ - r₂) (1 - cosθ)

B. (r₁ + r₂) (1 + cosθ)

C. (r₁ - r₂) [(1 - cosθ)/cos θ]

D. (r₁ + r₂) [(1 - cosθ)/cos θ]

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4

The mechanism forms a structure, when the number of degrees of freedom (n) is equal to

A. 0

B. 1

C. 2

D. -1

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4

In an open pair, the two elements of a pair

A. Have a surface contact when in motion

B. Have a line or point contact when in motion

C. Are kept in contact by the action of external forces, when in motion

D. Are not held together mechanically

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4

The approximate straight line mechanism is a

A. Four bar linkage

B. 6 bar linkage

C. 8 bar linkage

D. 3 bar linkage

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4

Kinematic pairs are those which have two elements that

A. Have line contact

B. Have surface contact

C. Permit relative motion

D. Are held together

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4

According to Kennedy's theorem, if three bodies have plane motions, their instantaneous centers lie on

A. A triangle

B. A point

C. Two lines

D. A straight line

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4

The periodic time of a compound pendulum is __________ when the distance between the point of suspension and the centre of gravity is equal to the radius of gyration of the body about its centre of gravity.

A. Zero

B. Minimum

C. Maximum

D. None of these

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4

The unbalanced primary forces in a reciprocating engine are

A. Balanced completely

B. Balanced partially

C. Balanced by secondary forces

D. Not balanced

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4

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)

A. ω² × OQ

B. ω² × OQ sinθ

C. ω² × OQ cosθ

D. ω² × OQ tanθ

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4

The D-slide valve is also known as

A. Inside admission valve

B. Outside admission valve

C. Piston slide valve

D. None of these

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4

The minimum number of teeth on the pinion which will mesh with any gear without interference for 20° full depth involute teeth will be

A. 12

B. 14

C. 18

D. 24

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4

Open pairs are those which have

A. Point or line contact between the two elements when in motion

B. Surface contact between the two elements when in motion

C. Elements of pairs not held together mechanically

D. Two elements that permit relative motion

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4

The frictional torque transmitted in a flat pivot bearing with assumption of uniform pressure is _________ as compared to uniform wear.

A. Less

B. More

C. Same

D. None of these

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4

The secondary unbalanced force is __________ the primary unbalanced force.

A. One-half

B. Two-third

C. n times

D. 1/n times

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4

In its simplest form, a cam mechanism consists of following number of links

A. 1

B. 2

C. 3

D. 4

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4

The height of a Watt's governor (in metres) is equal to (where N = Speed of the arm and ball about the spindle axis)

A. 8.95/N²

B. 89.5/N²

C. 895/N²

D. 8950/N²

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4

For S.H.M. cam, the acceleration of the follower at the ends of the stroke and aimed stroke respectively, is

A. Maximum and zero

B. Zero and maximum

C. Minimum and maximum

D. Zero and minimum

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4

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)

A. R (1 - cosθ)

B. (R - r₁) (1 - cosθ)

C. R (1 - sinθ)

D. (R - r₁) (1 - sinθ)

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4

The primary unbalanced force is maximum when the angle of inclination of the crank with the line of stroke is

A. 0° and 90°

B. 0° and 180°

C. 90° and 180°

D. 180° and 360°

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4

A friction circle is a circle drawn when a journal rotates in a bearing. Its radius depends upon the coefficient of friction and the

A. Magnitude of the forces on journal

B. Angular velocity of journal

C. Clearance between journal and bearing

D. Radius of journal

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4

The danger of breakage and vibration is maximum

A. Below the critical speed

B. Near the critical speed

C. Above the critical speed

D. None of these

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4

The engine of an aeroplane rotates in clockwise direction when seen from the tail end and the aeroplane takes a turn to the left. The effect of gyroscopic couple on the aeroplane will be

A. To dip the nose and tail

B. To raise the nose and tail

C. To raise the nose and dip the tail

D. To dip the nose and raise the tail

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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

Which of the following is an example of a higher pair?

A. Toothed gearing

B. Belt and rope drive

C. Ball and roller bearing

D. All of these

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4

When the axes of the first and last wheels are coaxial, then the train is known as

A. Simple train of wheels

B. Compound train of wheels

C. Reverted gear train

D. Epicyclic gear train

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4

The efficiency of a screw jack is maximum, when (where α = Helix angle, and φ = Angle of friction)

A. α = 45° + φ/2

B. α = 45° - φ/2

C. α = 90° + φ

D. α = 90° - φ

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4

A flywheel is fitted to the crankshaft of an engine having W as the amount of indicated work per revolution and permissible limits of coefficient of fluctuation of energy and speed as CE and CS respectively. The kinetic energy of the flywheel is given by

A. 2 W CE / CS

B. W CE / 2CS

C. W CE / CS

D. W CS / 2CE

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4

The maximum value of the pressure angle in case of cam is kept as

A. 10°

B. 14°

C. 20°

D. 30°

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4

The inversion of a mechanism is

A. Changing of a higher pair to a lower pair

B. Turning its upside down

C. Obtained by fixing different links in a kinematic chain

D. Obtained by reversing the input and output motion

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4

The working depth of a gear is the radial distance from the

A. Pitch circle to the bottom of a tooth

B. Pitch circle to the top of a tooth

C. Top of a tooth to the bottom of a tooth

D. Addendum circle to the clearance circle