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4

Which one of the following is an exact straight line mechanism using lower pairs?

A. Watts mechanism

B. Grasshopper mechanism

C. Roberts mechanism

D. Peaucelliers mechanism

Correct Answer :

D. Peaucelliers mechanism


Related Questions

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4

A point B on a rigid link AB moves with respect to A with angular velocity ω rad/s. The total acceleration of B with respect to A will be equal to

A. Vector sum of radial component and coriolis component

B. Vector sum of tangential component and coriolis component

C. Vector sum of radial component and tangential component

D. Vector difference of radial component and tangential component

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4

The unbalanced force due to revolving masses

A. Varies in magnitude but constant in direction

B. Varies in direction but constant in magnitude

C. Varies in magnitude and direction both

D. Constant in magnitude and direction both

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4

The maximum fluctuation of speed is the

A. Difference of minimum fluctuation of speed and the mean speed

B. Difference of the maximum and minimum speeds

C. Sum of maximum and minimum speeds

D. Variations of speed above and below the mean resisting torque line

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4

The radial distance of a tooth from the pitch circle to the bottom of the tooth is called

A. Dedendum

B. Addendum

C. Clearance

D. Working depth

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4

In locomotives, the ratio of the connecting rod length to me crank radius is kept very large in order to

A. Minimise the effect of primary forces

B. Minimise the effect of secondary forces

C. Have perfect balancing

D. To start the locomotive quickly

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4

The critical speed of a shaft depends upon its

A. Mass

B. Stiffness

C. Mass and stiffness

D. Stiffness and eccentricity

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4

A motor car moving at a certain speed takes a left turn in a curved path. If the engine rotates in the same direction as that of wheels, men due to centrifugal forc

A. The reaction on me inner wheels increases and on the outer wheels decreases

B. The reaction on the outer wheels increases and on the inner wheels decreases

C. The reaction on the front wheels increases and on the rear wheels decreases

D. The reaction on the rear wheels increases and on the front wheels decreases

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4

The sense of Coriolis component is such that it

A. Leads the sliding velocity vector by 90°

B. Lags the sliding velocity vector by 90°

C. Is along the sliding velocity vector

D. Leads the sliding velocity vector by 180°

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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

The frictional torque transmitted in a flat collar bearing, considering uniform wear, 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

The main disadvantage of the sliding pair is that it is

A. Bulky

B. Wears rapidly

C. Difficult to manufacture

D. Both (A) and (B) above

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4

Which of the following mechanism is an approximate straight line motion mechanism?

A. Watt's mechanism

B. Grasshopper mechanism

C. Robert's mechanism

D. All of these

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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

An eccentric sheave pivoted at one point rotates and transmits oscillatory motion to a link whose one end is pivoted and other end is connected to it. This mechanism has

A. 2 links

B. 3 links

C. 4 links

D. 5 links

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4

Balancing of rotating and reciprocating parts of an engine is necessary when it runs at

A. Slow speed

B. Moderate speed

C. Highs peed

D. Any one of these

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4

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

A. 0° and 90°

B. 180° and 360°

C. Both (A) and (B)

D. None of these

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4

In a four stroke I.C. engine, the turning moment during the compression stroke is

A. Positive throughout

B. Negative throughout

C. Positive during major portion of the stroke

D. Negative during major portion of the stroke

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4

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.

A. θ/2

B. θ

C.

D.

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4

Hammer blow

A. Is the maximum horizontal unbalanced force caused by the mass provided to balance the reciprocating masses.

B. Is the maximum vertical unbalanced force caused by the mass added to balance the reciprocating masses

C. Varies as the square root of the speed

D. Varies inversely with the square of the speed

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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

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4

The ratio of the maximum displacement of the forced vibration to the deflection due to the static force, is known as

A. Damping factor

B. Damping coefficient

C. Logarithmic decrement

D. Magnification factor

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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

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

A. ω² R cosθ

B. ω² (R - r₁) cosθ

C. ω² (R - r₁) sinθ

D. ω² r₁ sinθ

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4

The balancing of a rigid rotor can be achieved by appropriately placing balancing masses in

A. A single plane

B. Two planes

C. Three planes

D. Four planes

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4

Lower 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 maximum frictional force, which comes into play, when a body just begins to slide over the surface of the other body, is known as

A. Static friction

B. Dynamic friction

C. Limiting friction

D. Coefficient of friction

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4

A Porter governor is a

A. Pendulum type governor

B. Dead weight governor

C. Spring loaded governor

D. Inertia governor

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4

The ratio of height of Porter governor (when length of arms and links are equal) to the height of Watt's governor is (where m = Mass of the ball, and M = Mass on the sleeve)

A. m/(m + M)

B. M/(m + M)

C. (m + M)/m

D. (m + M)/M

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4

Sensitiveness of the governor is defined as the ratio of the

A. Mean speed to the maximum equilibrium speed

B. Mean speed to the minimum equilibrium speed

C. Difference of the maximum and minimum equilibrium speeds to the mean speed

D. Sum of the maximum and minimum equilibrium speeds to the mean speed

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4

Pulley in a belt drive acts as

A. Cylindrical pair

B. Turning pair

C. Rolling pair

D. Sliding pair