Machine Design MCQ Questions & Answers

51

If T is the actual number of teeth on a helical gear and $$\varphi $$ is the helix angle for the teeth, then formative number of teeth is written as

A) $${\text{T}}{\sec ^3}\varphi $$ B) $${\text{T}}{\sec ^2}\varphi $$ C) $$\frac{{\text{T}}}{{{{\sec }^3}\varphi }}$$ D) $${\text{Tcosec}}\varphi $$

Discuss

Answer & Solution

Answer: Option A

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52

In a flange coupling, the flanges are coupled together by means of

A) Bolts and nuts B) Studs C) Headless taper bolts D) None of these

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Answer & Solution

Answer: Option A

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53

A steel containing _________ 0.8% carbon is known as hypo-eutectoid steel.

A) Equal to B) Less than C) Greater than D) None of these

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Answer & Solution

Answer: Option B

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54

The application of third type levers is found in

A) A pair of tongs B) Hand wheel of a punching press C) Lever of a loaded safety valve D) Handle of a hand pump

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Answer & Solution

Answer: Option A

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55

The application of second type levers is found in

A) Handle of a hand pump B) Hand wheel of a punching press C) Lever of a loaded safety valve D) A pair of tongs

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Answer & Solution

Answer: Option C

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56

In composite or reverse laid ropes

A) Direction of twist of wires in strands is opposite to the direction of twist of strands B) Direction of twist of wires and strands are same C) Wires in two adjacent strands are twisted in opposite direction D) Wires are not twisted

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Answer & Solution

Answer: Option C

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57

In the assembly of pulley, key and shaft

A) Pulley is made the weakest B) Key is made the weakest C) Key is made the strongest D) All the three are designed for equal strength

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Answer & Solution

Answer: Option B

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58

The groove angle of pulleys for V-belt is

A) 34° to 36° B) 42° to 45° C) More than 45° D) 30° to 32°

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Answer & Solution

Answer: Option A

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59

When the speed of belt increases,

A) The coefficient of friction between the belt and pulley decreases B) The coefficient of friction between the belt and pulley increases C) The power transmitted will decrease D) The power transmitted will increase

Discuss

Answer & Solution

Answer: Option D

Solution:

When the speed of the belt increases

The power transmitted by a belt drive is directly proportional to the product of the belt tension and the belt speed

Power (P) = (T₁ - T₂) × v, where T₁ is the tension in the tight side, T₂ is the tension in the slack side, and v is the belt speed

As the belt speed increases, assuming the tensions remain constant, the power transmitted also increases

However, there's a practical limit to this, because at very high speeds, centrifugal force increases and reduces the effective friction and tension difference

But initially, with an increase in speed, the power transmitted increases

60

For unequal width of butt straps, the thicknesses of butt straps are

A) 0.75 t for narrow strap on the inside and 0.625 t for wide strap on the outside B) 0.75 t for wide strap on the inside and 0.625 t for narrow strap on the outside C) 0.75 t for both the straps on the inside and outside D) 0.625 t for both the straps on the inside and outside

Discuss

Answer & Solution

Answer: Option B

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Machine Design MCQ Questions & Answers | Mechanical Engineering