Machine Design MCQ Questions & Answers

51

Two closely coiled helical springs with stiffness k₁ and k₂ respectively are connected in series. The stiffness of an equivalent spring is given by

A) $$\frac{{{{\text{k}}_1}{{\text{k}}_2}}}{{{{\text{k}}_1} + {{\text{k}}_2}}}$$ B) $$\frac{{{{\text{k}}_1} - {{\text{k}}_2}}}{{{{\text{k}}_1} + {{\text{k}}_2}}}$$ C) $$\frac{{{{\text{k}}_1} + {{\text{k}}_2}}}{{{{\text{k}}_1}{{\text{k}}_2}}}$$ D) $$\frac{{{{\text{k}}_1} - {{\text{k}}_2}}}{{{{\text{k}}_1}{{\text{k}}_2}}}$$

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Answer & Solution

Answer: Option A

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52

For same pulley diameters, center distance, belt speed and belt and pulley materials,

A) Open belt drive transmits more power than crossed belt drive B) Crossed belt drive transmits more power than open belt drive C) Open and crossed belt drives transmit same power D) Power transmission does not depend upon open and crossed types of constructions

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Answer & Solution

Answer: Option B

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53

Two shafts will have equal strength, if

A) Diameter of both the shafts is same B) Angle of twist of both the shafts is same C) Material of both the shafts is same D) Twisting moment of both the shafts is same

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Answer & Solution

Answer: Option D

Solution:

Two shafts will have equal strength if the twisting moment of both the shafts is the same.

Twisting moment determines the ability of a shaft to resist the applied torque without failure. It is given by the formula:

T = τ × Z_p

Where:

T = Twisting moment

τ = Shear stress

Z_p = Polar section modulus

Equal twisting moments imply that the shafts will experience the same level of stress and deformation under the applied torque, ensuring they have equal strength.

Therefore, Option D is the correct answer.

54

The draw of cotter need not exceed

A) 3 mm B) 5 mm C) 10 mm D) 20 mm

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Answer & Solution

Answer: Option A

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55

For a bevel gear having the pitch angle $$\theta $$, the ratio of formative number of teeth (TE) to actual number of teeth (T) is

A) $$\frac{1}{{\sin \theta }}$$ B) $$\frac{1}{{\cos \theta }}$$ C) $$\frac{1}{{\tan \theta }}$$ D) $$\sin \theta \cos \theta $$

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Answer & Solution

Answer: Option B

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56

Crushing resistance required to crush the rivet per pitch length is

A) $${\text{pd}}{\sigma _{\text{c}}}$$ B) $${\text{pt}}{\sigma _{\text{c}}}$$ C) $${\text{ndt}}{\sigma _{\text{c}}}$$ D) $$\left( {{\text{p}} - {\text{d}}} \right){\text{t}}{\sigma _{\text{c}}}$$

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Answer & Solution

Answer: Option C

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57

Tearing resistance required to tear off the plate per pitch length is (where p = Pitch of rivets, d = Dia. of rivet hole and $${\sigma _{\text{t}}}$$ = Permissible tensile stress for plate material)

A) $${\text{pd}}{\sigma _{\text{t}}}$$ B) $${\text{pt}}{\sigma _{\text{t}}}$$ C) $$\left( {{\text{p}} - {\text{d}}} \right){\sigma _{\text{t}}}$$ D) $$\left( {{\text{p}} - {\text{d}}} \right){\text{t}}{\sigma _{\text{t}}}$$

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Answer & Solution

Answer: Option D

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58

Which of the following welded joint is designed for shear strength?

A) Transverse fillet welded joint B) Parallel fillet welded joint C) Butt welded joint D) All of these

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Answer & Solution

Answer: Option B

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59

Fibrous fracture occurs in

A) Ductile material B) Brittle material C) Elastic material D) Hard material

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Answer & Solution

Answer: Option A

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60

The ratio of belt tensions $$\frac{{{{\text{p}}_1}}}{{{{\text{p}}_2}}}$$ considering centrifugal force in flat belt is given by where,
m = mass of belt per meter (kg/m)
v = belt velocity (m/s)
f = coefficient of friction
$$\alpha $$ = angle of wrap (radians)

A) $$\frac{{{{\text{p}}_1} - {\text{m}}{{\text{v}}^2}}}{{{{\text{p}}_2} - {\text{m}}{{\text{v}}^2}}} = {{\text{e}}^{{\text{f}}\alpha }}$$ B) $$\frac{{{{\text{p}}_1}}}{{{{\text{p}}_2}}} = {{\text{e}}^{{\text{f}}\alpha }}$$ C) $$\frac{{{{\text{p}}_1}}}{{{{\text{p}}_2}}} = {{\text{e}}^{ - {\text{f}}\alpha }}$$ D) $$\frac{{{{\text{p}}_1} - {\text{m}}{{\text{v}}^2}}}{{{{\text{p}}_2} - {\text{m}}{{\text{v}}^2}}} = {{\text{e}}^{ - {\text{f}}\alpha }}$$

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Answer & Solution

Answer: Option A

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Machine Design MCQ Questions & Answers | Mechanical Engineering