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4

The equation of free vibrations of a system is (d²x/dt²) +36 π²x, its natural frequency is

A. 3 Hz

B. 3π Hz

C. 6 Hz

D. 6π Hz

Correct Answer :

A. 3 Hz


Related Questions

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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

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 arrangement is called bevel gearing, when two __________ are connected by gears.

A. Intersecting and coplanar shafts

B. Nonintersecting and non-coplanar shafts

C. Parallel and coplanar shafts

D. Parallel and non-coplanar shafts

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4

An exact straight line motion mechanism is a

A. Scott-Russell's mechanism

B. Hart's mechanism

C. Peaucellier's mechanism

D. All of these

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4

The frictional torque transmitted by a disc or plate clutch is same as that of

A. Flat pivot bearing

B. Flat collar bearing

C. Conical pivot bearing

D. Truncated conical pivot bearing

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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 dedendum circle diameter is equal to (where, φ = Pressure angle)

A. Pitch circle dia. × cosφ

B. Addendum circle dia. × cosφ

C. Clearance circle dia. × cosφ

D. Pitch circle dia. × sinφ

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4

The example of lower pair is

A. Shaft revolving in a bearing

B. Straight line motion mechanisms

C. Automobile steering gear

D. All of the above

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4

Whitworth quick return mechanism is obtained by inversion of

A. Slider crank mechanism

B. Kinematic chain

C. Five link mechanism

D. Roller cam mechanism

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4

To connect two parallel and coplanar shafts the following type of gearing is used

A. Spur gear

B. Bevel gear

C. Spiral gear

D. None of the above

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4

The velocity of a body moving with simple harmonic motion is __________ at the mean position.

A. Zero

B. Minimum

C. Maximum

D. None of these

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4

A typewriter mechanism has 7 numbers of binary joints, six links and none of higher pairs. The mechanism is

A. Kinematically sound

B. Not sound

C. Soundness would depend upon which link is kept fixed

D. Data is not sufficient to determine same

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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

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 gears are termed as medium velocity gears, if their peripheral velocity is

A. 1-3 m/s

B. 3-15 m/s

C. 15-30 m/s

D. 30-50 m/s

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4

A shaft carrying three rotors will have

A. No node

B. One node

C. Two nodes

D. Three nodes

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4

When the crank is at the inner dead centre, in a reciprocating steam engine, then the acceleration of the piston will be

A. ω²r. (n + 1)/n

B. ω²r. (n - 1)/n

C. ω²r. n/(n + 1)

D. ω²r. n/(n - 1)

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4

The transmissibility, for all values of damping factor, will be less than unity, if ω/ωn is

A. Equal to 1

B. Less than 2

C. Equal to 2

D. Greater than 2

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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

When the body is suspended at the point of suspension, its periodic time and frequency will be ________ as compared to the body suspended at the point of percussion.

A. Same

B. Two times

C. Four times

D. None of these

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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

Which is the false statement about the properties of instantaneous centre?

A. At the instantaneous center of rotation, one rigid link rotates instantaneously relative to another for the configuration of mechanism considered

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

C. The two rigid links which have no linear velocity relative to each other at this center have the same linear velocity to the third rigid link

D. The double centre can be denoted either by O2 or O12, but proper selection should be made

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4

The coriolis component of acceleration exists whenever a point moves along a path that has

A. Linear displacement

B. Rotational motion

C. Gravitational acceleration

D. Tangential acceleration

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4

For the same lift and same angle of ascent, a smaller base circle will give

A. A small value of pressure angle

B. A large value of pressure angle

C. There is no such relation with pressure angle

D. Something else

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4

The train value of a gear train is

A. Equal to velocity ratio of a gear train

B. Reciprocal of velocity ratio of a gear train

C. Always greater than unity

D. Always less than unity

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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

Which of the following is an inversion of Single slider crank chain?

A. Beam engine

B. Rotary engine

C. Oldhams coupling

D. Elliptical trammel

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4

The mechanism consisting of three turning pairs and one sliding pair, is called a

A. Single slider crank chain

B. Whitworth quick return motion mechanism

C. Crank and slotted lever quick return motion mechanism

D. All of the above

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4

Which of the following mechanisms produces mathematically an exact straight line motion?

A. Grasshopper mechanism

B. Watt mechanism

C. Peaucellier's mechanism

D. Tchebicheff mechanism

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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