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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

Correct Answer :

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


Related Questions

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4

The driving and driven shafts connected by a Hooke's joint will have equal speeds, if

A. cosθ = sinα

B. sinθ = ± tanα

C. tanθ = ± cosα

D. cotθ = cosα

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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

Angle of descent of cam is defined as the angle

A. During which the follower returns to its initial position

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

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

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

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4

A Hartnell governor is a

A. Dead weight governor

B. Pendulum type governor

C. Spring loaded governor

D. Inertia governor

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4

A slider moves at a velocity v on a link revolving at ω rad/s. The coriolis component of acceleration is

A. ωv

B. 2ωv

C. ω²v

D. 2ωv²

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4

The two elements of a pair are said to form a higher pair, when they

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. Permit relative motion

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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

When a point moves along a straight line, its acceleration will have

A. Radial component only

B. Tangential component only

C. Coriolis component only

D. Radial and tangential components both

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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 disc is a spinning with an angular velocity ω rad/s about the axis of spin. The couple applied to the disc causing precession will be (where I = Mass moment of inertia of the disc, and ωP = Angular velocity of precession of the axis of spin)

A. (1/2).Iω²

B. Iω²

C. (1/2). I ω ωP

D. I ω ωP

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4

In a cam drive with uniform velocity follower, the sharp corners of the displacement diagram are rounded off at the beginning and at the end of each stroke. This is done

A. Because of difficulty in manufacturing cam profile

B. Because of loose contact of follower with cam surface

C. In order to have acceleration in beginning and retardation at the end of stroke within the finite limits

D. Because the uniform velocity motion is a partial parabolic motion

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4

The method of direct and reverse cranks is used in engines for

A. The control of speed fluctuations

B. Balancing of forces and couples

C. Kinematic analysis

D. Vibration analysis

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4

A pantograph is a mechanism with

A. Lower pairs

B. Higher pairs

C. Rolling pairs

D. Turning pairs

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4

In order to give a complete secondary balance of a multi-cylinder inline engine,

A. The algebraic sum of the secondary forces must be equal to zero

B. The algebraic sum of the couples about any point in the plane of the secondary forces must be equal to zero

C. Both (A) and (B)

D. None of these

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4

The frictional torque transmitted in a truncated conical pivot bearing, considering uniform wear, is

A. (1/2). μ W cosec α (r₁ + r₂)

B. (2/3).μ W cosec α (r₁ + r₂)

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

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

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4

Two pulleys of radii r₁ and r₂ and at distance x apart are connected by means of an open belt drive. The length of the belt is

A. π (r₁ + r₂) + (r₁ + r₂)²/x + 2x

B. π (r₁ + r₂) + (r₁ - r₂)²/x + 2x

C. π (r₁ - r₂) + (r₁ - r₂)²/x + 2x

D. π (r₁ - r₂) + (r₁ + r₂)²/x + 2x

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4

For the brake to be self locking, the force P at C shown in the below figure, should

A. Be zero

B. Act in upward direction

C. Act in downward direction

D. None of these

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4

The tractive force is maximum or minimum when the angle of inclination of crank with the line of stroke (θ) is equal to

A. 0° and 90°

B. 90° and 180°

C. 135° and 315°

D. 270° and 360°

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4

The ratio of the driving tensions for V-belts is __________ times that of flat belts. (Where β = Semi-angle of the groove)

A. sinβ

B. cosβ

C. cosecβ

D. secβ

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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 instantaneous centres which vary with the configuration of mechanism are called

A. Permanent instantaneous centres

B. Fixed instantaneous centres

C. Neither fixed nor permanent instantaneous centres

D. None of the above

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4

If the controlling force line for a spring controlled governor when produced intersects the Y-axis at the origin, then the governor is said to be

A. Stable

B. Unstable

C. Isochronous

D. None of these

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4

Which of the following statement is wrong?

A. A round bar in a round hole form a turning pair

B. A square bar in a square hole form a sliding pair

C. A vertical shaft in a foot step bearing forms a successful constraint

D. All of the above

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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

A body of weight W is required to move up the rough inclined plane whose angle of inclination with the horizontal is α. The effort applied parallel to the plane is given by (where μ = tan φ = Coefficient of friction between the plane and the body)

A. P = W tan α

B. P = W tan (α + φ)

C. P = W (sin α + μ cos α)

D. P = W (cos α + μ sin α)

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4

The rotor of a ship rotates in clockwise direction when viewed from stern and the ship takes a left turn. The effect of gyroscopic couple acting on it will be

A. To raise the bow and stern

B. To lower the bow and stern

C. To raise the bow and lower the stern

D. To raise the stern and lower the bow

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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

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

When two links are connected by a pin joint, their instantaneous centre lies

A. On their point of contact

B. At the centre of curvature

C. At the centre of circle

D. At the pin joint

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4

Which of the following is an inversion of a single slider crank chain?

A. Pendulum pump

B. Oscillating cylinder engine

C. Rotary internal combustion engine

D. All of these