Theory Of Machine MCQ Questions & Answers

71

A pulley and belt in a belt drive form a

A) Cylindrical pair B) Turning pair C) Rolling pair D) Sliding pair

Discuss

Answer & Solution

Answer: Option C

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72

Elements of pairs held together mechanically is known as

A) Closed pair B) Open pair C) Mechanical pair D) Rolling pair

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Answer & Solution

Answer: Option A

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73

Carnot cycle is

A) A reversible cycle B) An irreversible cycle C) A semi-reversible cycle D) A quasi static cycle

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Answer & Solution

Answer: Option A

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74

The unbalanced primary forces in a reciprocating engine are

A) Balanced completely B) Balanced partially C) Balanced by secondary forces D) Not balanced

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Answer & Solution

Answer: Option B

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75

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 force

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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Answer & Solution

Answer: Option B

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76

If the radius of gyration of a compound pendulum about an axis through e.g. is more, then its frequency of oscillation will be

A) Less B) More C) Same D) Data are insufficient to determine same

Discuss

Answer & Solution

Answer: Option A

Solution:

The frequency of oscillation of a compound pendulum is inversely proportional to the radius of gyration about the axis of rotation. The radius of gyration (k) is a measure of how mass is distributed relative to the axis of rotation. A larger radius of gyration means the mass is more spread out, leading to a lower frequency of oscillation.

Let's analyze each option:

Option A: "Less" - This is correct because a larger radius of gyration results in a longer period of oscillation, thus reducing the frequency.

Option B: "More" - This is incorrect as frequency decreases with an increase in the radius of gyration.

Option C: "Same" - This is incorrect because frequency and radius of gyration are inversely related.

Option D: "Data are insufficient to determine same" - This is incorrect because the relationship between frequency and radius of gyration is well-established in physics.

Therefore, the correct answer is Option A: Less.

77

In gramophones for adjusting the speed of the turntable, the following type of governor is commonly employed

A) Hartung governor B) Wilson Hartnell governor C) Pickering governor D) Inertia governor

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Answer & Solution

Answer: Option C

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78

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 increases D) Remain constant for all radii of rotation

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Answer & Solution

Answer: Option D

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79

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 increases D) Remains constant for all radii of rotation

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Answer & Solution

Answer: Option C

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80

A shaft has two heavy rotors mounted on it. The transverse natural frequencies, considering each of the rotor separately, are 100 Hz and 200 Hz respectively. The lowest critical speed is

A) 5,367 r.p.m. B) 6,000 r.p.m. C) 9,360 r.p.m. D) 12,000 r.p.m.

Discuss

Answer & Solution

Answer: Option A

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Theory Of Machine MCQ Questions & Answers | Mechanical Engineering