## Machine Design MCQ Set 1

1. 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 the maximum and minimum speeds

d) variations of speed above and below the mean resisting torque line

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2. The coefficient of fluctuation of speed is the _________ of maximum fluctuation of speed and the mean speed.

a) product

b) ratio

c) sum

d) difference

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3. In a turning moment diagram, the variations of energy above and below the mean resisting torque line is called

a) fluctuation of energy

b) maximum fluctuation of energy

c) coefficient of fluctuation of energy

d) none of the mentioned

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4. If E = Mean kinetic energy of the flywheel, C_{S} = Coefficient of fluctuation of speed and Δ E = Maximum fluctuation of energy, then

a) ΔE = E / C_{S}

b) ΔE = E^{2} × C_{S}

c) ΔE = E × C_{S}

d) ΔE = 2 E × C_{S}

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_{S}

5. The ratio of the maximum fluctuation of energy to the ……. is called coefficient of fluctuation of energy.

a) minimum fluctuation of energy

b) workdone per cycle

c) maximum fluctuation of energy

d) none of the mentioned

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6. Due to the centrifugal force acting on the rim, the flywheel arms will be subjected to

a) tensile stress

b) compressive stress

c) shear stress

d) none of the mentioned

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7. The tensile stress in the flywheel rim due to the centrifugal force acting on the rim is given by

a) ρ v^{2}/4

b) ρ v^{2}/2

c) 3ρ v^{2}/4

d) ρ v^{2}

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^{2}

where ρ = Density of the flywheel material, and v = Linear velocity of the flywheel.

8. The cross-section of the flywheel arms is usually

a) elliptical

b) rectangular

c) I-section

d) L-section

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9. In order to find the maximum bending moment on the arms, it is assumed as a

a) simply supported beam carrying a uniformly distributed load over the arm

b) fixed at both ends

c) cantilever beam fixed at the hub and carrying a concentrated load at the free end of the rim

d) none of the mentioned

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10. The diameter of the hub of the flywheel is usually taken

a) equal to the diameter of the shaft

b) twice the diameter of the shaft

c) three times the diameter of the shaft

d) four times the diameter of the shaft

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## Machine Design MCQ Set 2

1. 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 the maximum and minimum speeds

d) variations of speed above and below the mean resisting torque line

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2. The coefficient of fluctuation of speed is the _____________ of maximum fluctuation of speed and the mean speed.

a) product

b) ratio

c) sum

d) difference

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3. In a turning moment diagram, the variations of energy above and below the mean resisting torque line is called

a) fluctuation of energy

b) maximum fluctuation of energy

c) coefficient of fluctuation of energy

d) none of the mentioned

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4. If E = Mean kinetic energy of the flywheel, C_{S} = Coefficient of fluctuation of speed and Δ E = Maximum fluctuation of energy, then

a) ΔE = E / C_{S}

b) ΔE = E^{2} × C_{S}

c) ΔE = E × C_{S}

d) ΔE = 2 E × C_{S}

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_{S}

5. The ratio of the maximum fluctuation of energy to the ___________ is called coefficient of fluctuation of energy.

a) minimum fluctuation of energy

b) workdone per cycle

c) coefficient of fluctuation of energy

d) none of the mentioned

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_{E}.

6. Due to the centrifugal force acting on the rim, the flywheel arms will be subjected to

a) tensile stress

b) compressive stress

c) shear stress

d) none of the mentioned

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7. The tensile stress in the flywheel rim due to the centrifugal force acting on the rim is given by

a) ρ v^{2}/4

b) ρ v^{2}/2

c) 3ρ v^{2}/4

d) ρ v^{2}

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^{2}

where ρ = Density of the flywheel material, and v = Linear velocity of the flywheel.

8. The cross-section of the flywheel arms is usually

a) elliptical

b) rectangular

c) I-section

d) L-section

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9. In order to find the maximum bending moment on the arms, it is assumed as a

a) simply supported beam carrying a uniformly distributed load over the arm

b) fixed at both ends (i.e. at the hub and at the free end of the rim) and carrying a uniformly distributed load over the arm.

c) cantilever beam fixed at the hub and carrying a concentrated load at the free end of the rim

d) none of the mentioned

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10. The diameter of the hub of the flywheel is usually taken

a) equal to the diameter of the shaft

b) twice the diameter of the shaft

c) three times the diameter of the shaft

d) four times the diameter of the shaft

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## Machine Design MCQ Set 3

1. 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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2. The maximum fluctuation of energy is the

a) difference between the maximum and minimum energies

b) sum of the maximum and minimum energies

c) variations of energy above and below the mean resisting torque to the

d) ratio of the mean resisting torque to the workdone per cycle

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3. The co-efficient of fluctuation of energy is the ratio of maximum energy to the minimum energy.

a) True

b) False

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4. Which of the following statement is wrong?

a) The difference between the maximum and minimum energies is called maximum fluctuation of energy.

b) The co-efficient of fluctuation of speed is the ratio of maximum fluctuation of speed to the mean speed.

c) The variations of energy above and below the mean resisting torque line is known as fluctuation of energy.

d) None of the mentioned

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5. The ratio of maximum fluctuation of energy to the workdone per cycle is called

a) fluctuation of energy

b) maximum fluctuation of energy

c) coefficient of fluctuation of speed

d) none of the mentioned

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6. Maximum fluctuation of energy in a flywheel is equal to

a) Iω(ω_{1} – ω_{2})

b) Iω^{2}C_{S}

c) 2EC_{S}

d) all of the mentioned

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7. 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 C_{E} and C_{S} respectively. The kinetic energy of the flywheel is given by

a) 2WC_{E}/C_{S}

b) WC_{E}/2C_{S}

c) WC_{E}/C_{S}

d) WC_{S}/2C_{E}

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8. If the rotating mass of a rim type flywheel is distributed on another rim type flywheel whose mean radius is half the mean radius of the former, then energy stored in the latter at the same speed will be

a) four times the first one

b) same as the first one

c) one fourth of the first one

d) one and a half times the first one

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

a) fluctuation of energy

b) maximum fluctuation of energy

c) coefficient of fluctuation of speed

d) none of the mentioned

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10. The flywheel of a machine having weight of 4500 N and radius of gyration of 2 m has cyclic fluctuation of speed from 125 r.p.m to 120 r.p.m. Assuming g = 10m/s^{2}, the maximum fluctuation of energy is

a) 12822 N-m

b) 24200 N-m

c) 14822 N-m

d) 12100 N-m

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^{2}= 1800 kgm

^{2}

ω_{1} = 2π/60 x 125rad/sec

ω_{2} = 2π/60 x 120rad/sec

E_{max} = 1/2 I(?)^{2} = 12087.2 N-m
= 12100 Nm

11. A circular solid disc of uniform thickness 20 mm, radius 200 mm and mass 20 kg, is used as a flywheel. If it rotates at 600 rpm, the kinetic energy of the flywheel, in Joules is

a) 395

b) 790

c) 1580

d) 3160

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^{2}ω = 2πN/60 = 62.83 rad/s

I (for solid circular disk) = 1/2mR^{2} = 0.4 kg m^{2} Hence, K.E = 790 Joules.

12. The speed of an engine varies from 210 rad/s to 190 rad/s. During the cycle the change in kinetic energy is found to be 400 Nm. The inertia of the flywheel in kg/m2 is

a) 0.10

b) 0.20

c) 0.30

d) 0.40

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_{1}= 210 rad/ sec, ω

_{2}= 190 rad/ sec, ΔE= 400 Nm As the speed of flywheel changes from ω

_{1}to ω

_{2}, the maximum fluctuation of energy,

ΔE = 1/2I [(ω_{1})^{2} (ω_{2})^{2}]
I = 0.10 kgm^{2}

13. For a certain engine having an average speed of 1200 rpm, a flywheel approximated as a solid disc, is required for keeping the fluctuation of speed within 2% about the average speed. The fluctuation of kinetic energy per cycle is found to be 2 kJ. What is the least possible mass of the flywheel if its diameter is not to exceed 1 m ?

a) 40 kg

b) 51 kg

c) 62 kg

d) 73 kg

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_{s}= 0.02 Mean angular speed of engine, ω = 2πN/60 = 125.66 rad/ sec

Fluctuation of energy of the flywheel is given by,
ΔE = Iω^{2}C_{s} = 1/2mR^{2}ω^{2}C_{s} For solid disc I = mR^{2}/2
m = 51 kg

## Machine Design MCQ Set 4

1. The axis of precession is ____________ to the plane in which the axis of spin is going to rotate.

a) parallel

b) perpendicular

c) spiral

d) none of the mentioned

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2. 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

a) 1/2 Iω^{2}

b) Iω^{2}

c) 1/2 Iωω_{p}

d) Iωω_{p}

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3. 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 of the tail

d) to dip the nose and raise the tail

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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 right. The effect of gyroscopic couple on the aeroplane will be to dip the nose and raise the tail.

a) True

b) False

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5. The steering of a ship means

a) movement of a complete ship up and down in vertical plane about transverse axis

b) turning of a complete ship in a curve towards right or left, while it moves forward

c) rolling of a complete ship side-ways

d) none of the mentioned

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6. The rolling of a complete ship side-ways is known as pitching of a ship.

a) True

b) False

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7. 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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8. The rotor of a ship rotates in clockwise direction when viewed from stern and the ship takes a right turn. The effect of gyroscopic couple acting on it will be to raise the stern and lower the bow.

a) True

b) False

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9. The pitching of a ship is assumed to take place with simple harmonic motion.

a) True

b) False

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10. When the pitching of a ship is upward, the effect of gyroscopic couple acting on it will be

a) to move the ship towards star-board

b) to move the ship towards port side

c) to raise the bow and lower the stern

d) to raise the stern and lower the bow

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## Machine Design MCQ Set 5

1. Power of a governor is the

a) mean force exerted at the sleeve for a given percentage change of speed

b) workdone at the sleeve for maximum equilibrium speed

c) mean force exerted at the sleeve for maximum equilibrium speed

d) none of the mentioned

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2. The effort of a Porter governor is equal to

a) c(m – M)g

b) c(m + M)g

c) C/(m + M)g

d c/(m – M)g

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^{2}/1 + 2c (m + M)gh.

3. The power of a Porter governor is equal to

a) c^{2}/1 + 2c (m + M)gh

b) 2c^{2}/1 + 2c (m + M)gh

c) 3c^{2}/1 + 2c (m + M)gh

d) 4c^{2}/1 + 2c (m + M)gh

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^{2}/1 + 2c (m + M)gh.

4. For the isochronous Porter governor, the controlling force curve is a straight line passing through the origin.

a) True

b) False

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5. The controlling force diagram for a spring controlled governor is a curve passing through the origin.

a) True

b) False

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6. A spring controlled governor is said to be unstable when the controlling force

a) increases as the radius of rotation decreases

b) increases as the radius of rotation increases

c) decreases as the radius of rotation decreases

d) remains constant for all radii of rotation

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7. In a spring controlled governor, when the controlling force _____________ as the radius of rotation increases, it is said to be a stable governor.

a) remains constant

b) decreases

c) increases

d) none of the mentioned

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8. A spring controlled governor is said to be isochronous when the controlling force

a) increases as the radius of rotation decreases

b) increases as the radius of rotation increases

c) decreases as the radius of rotation decreases

d) remains constant for all radii of rotation

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9. A spring controlled governor is found unstable. It can be made stable by

a) increasing the spring stiffness

b) decreasing the spring stiffness

c) increasing the ball mass

d) decreasing the ball mass

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10. 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 of the mentioned