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4

The maximum efficiency of a screw jack is

A. (1 - sinφ)/(1 + sinφ)

B. (1 + sinφ)/(1 - sinφ)

C. (1 - tanφ)/(1 + tanφ)

D. (1 + tanφ)/(1 - tanφ)

Correct Answer :

A. (1 - sinφ)/(1 + sinφ)


Related Questions

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4

The fundamental equation for correct steering is (where φ and α = Angle through which the axis of the outer wheel and inner wheel turns respectively, c = Distance between the pivots of the front axles, and d = Wheel base)

A. sinφ + sinα = b/c

B. cosφ - sinα = c/b

C. cotφ - cotα = c/b

D. tanφ + cotα = b/c

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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

For high speed engines, the cam follower should move with

A. Uniform velocity

B. Simple harmonic motion

C. Uniform acceleration and retardation

D. Cycloidal motion

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4

In a steam engine, one method of obtaining the earlier cut-off with a simple slide valve is by increasing the angle of advance of the eccentric while the throw of the eccentric, steam lap and exhaust lap are kept constant. 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

The velocity of piston in a reciprocating steam engine is given by (where ω = Angular velocity of crank, r = Radius of crank pin circle, θ = Angle turned by crank from inner dead centre, and n = Ratio of length of connecting rod to the radius of crank)

A. ωr [sin θ + (sin 2θ/n)]

B. ωr [cos θ + (cos 2θ/n)]

C. ω²r [sin θ + (sin 2θ/n)]

D. ω²r [cos θ + (cos 2θ/n)]

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4

To transmit power from one rotating shaft to another whose axes are neither parallel nor intersecting, use?

A. Spur gear

B. Spiral gear

C. Bevel gear

D. Worm gear

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4

The balancing weights are introduced in planes parallel to the plane of rotation of the disturbing mass. To obtain complete dynamic balance, the minimum number of balancing weights to be introduced in different planes is

A. 1

B. 2

C. 3

D. 4

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4

If D₁ and D₂ be the diameters of driver and driven pulleys, then belt speed is proportional to

A. D₁/D₂

B. D₂/D₁

C. D₁.D₂

D. D₁

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4

The frictional torque transmitted in a flat collar bearing, considering uniform pressure, is (where r₁ and r₂ = External and internal radii of collar respectively)

A. (1/2). μ W (r₁ + r₂)

B. (2/3). μ W (r₁ + r₂)

C. (1/2). μ W [(r₁³ - r₂³)/(r₁² - r₂²)]

D. (2/3). μ W [(r₁³ - r₂³)/(r₁² - r₂²)]

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4

In a drag link quick return mechanism, the shortest link is always fixed. The sum of the shortest and longest link is

A. Equal to sum of other two

B. Greater than sum of other two

C. Less than sum of other two

D. There is no such relationship

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4

Which type of gear train is used in clock mechanism to join hour hand and minute hand?

A. Simple gear train

B. Compound gear train

C. Reverted gear train

D. Epicyclic gear train

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4

In Meyer's expansion valve, the expansion valve is driven by an eccentric having an angle of advance from

A. 50°-60°

B. 60°-70°

C. 70°-80°

D. 80°-90°

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4

When the particles of a body moves perpendicular to its axis, then the body is said to have

A. Longitudinal vibration

B. Transverse vibration

C. Torsional vibration

D. None of these

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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

Which of the following governor is used to drive a gramophone?

A. Watt governor

B. Porter governor

C. Pickering governor

D. Hartnell governor

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4

It is required to connect two parallel shafts, the distance between whose axes is small and variable. The shafts are coupled by

A. Universal joint

B. Knuckle joint

C. Oldham's coupling

D. Flexible coupling

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4

In a circular arc cam with roller follower, the acceleration in any position of the lift will depend only upon

A. Total lift, total angle of lift, minimum radius of cam and cam speed

B. Radius of circular arc, cam speed, location of centre of circular arc and roller diameter

C. Mass of cam follower linkage, spring stiffness and cam speed

D. Total lift, centre of gravity of the cam and cam speed

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4

In a four bar chain or quadric cycle chain

A. Each of the four pairs is a turning pair

B. One is a turning pair and three are sliding pairs

C. Two are turning pairs and two are sliding pairs

D. Three are turning pairs and one is a sliding pair

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4

The amplitude of vibration is always __________ the radius of the circle.

A. Equal to

B. Less than

C. Greater than

D. None of these

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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

The partial balancing of reciprocating parts in locomotives produces

A. Hammer blow

B. Swaying couple

C. Variation in tractive force along the line of stroke

D. All of the above

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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 spring controlled governor is said to be stable if the controlling force line when produced intersects the Y-axis

A. At the origin

B. Below the origin

C. Above the origin

D. Any one of these

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4

Instantaneous center of rotation of a link in a four bar mechanism lies on

A. Right side pivot of this link

B. Left side pivot of this link

C. A point obtained by intersection on extending adjoining links

D. Cant occur

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4

The example of spherical pair is

A. Bolt and nut

B. Lead screw of a lathe

C. Ball and socket joint

D. Ball bearing and roller bearing

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4

The ratio of maximum fluctuation of speed to the mean speed is called

A. Fluctuation of speed

B. Maximum fluctuation of speed

C. Coefficient of fluctuation of speed

D. None of these

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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

Which gear train is used for higher velocity ratios in a small space?

A. Simple gear train

B. Compound gear train

C. Reverted gear train

D. Epicyclic gear train

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4

The length of a simple pendulum which gives the same frequency as the compound pendulum, is

A. kG + l₁

B. kG² + l₁

C. (kG² + l₁²)/ l₁

D. (kG + l₁²)/ l₁

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4

Which gear is used for connecting two coplanar and intersecting shafts?

A. Spur gear

B. Helical gear

C. Bevel gear

D. None of the above