Machine Design - Study Mode

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[#171] The speed of the sprocket reduces as the chain pitch __________ for a given number of teeth.

(A) Increases

(B) Decreases

(C) Remain same

(D) None of these

Correct Answer

(A) Increases

[#172] A shaft is subjected to a maximum bending stress of 80 N/mm 2 and maximum shearing stress equal to 30 N/mm 2 at a particular section. If the yield point in tension of the material is 280 N/mm 2 and the maximum shear stress theory of failure is used, then the factor of safety obtained will be

(A) 2.5

(B) 2.8

(C) 3.0

(D) 3.5

Correct Answer

(B) 2.8

[#173] The stiffness of a closely coiled helical spring subjected to an axial load W is equal to (where G = Modulus of rigidity and n = Number of active coils)

(A) $$frac{{{ ext{G}}{{ ext{d}}^4}}}{{8{{ ext{D}}^3}{ ext{n}}}}$$

(B) $$frac{{{ ext{G}}{{ ext{d}}^3}}}{{8{{ ext{D}}^3}{ ext{n}}}}$$

(C) $$frac{{{ ext{G}}{{ ext{d}}^4}}}{{4{{ ext{D}}^3}{ ext{n}}}}$$

(D) $$frac{{{ ext{G}}{{ ext{d}}^4}}}{{8{{ ext{D}}^2}{ ext{n}}}}$$

Correct Answer

(A) $$frac{{{ ext{G}}{{ ext{d}}^4}}}{{8{{ ext{D}}^3}{ ext{n}}}}$$

[#174] For longitudinal joint in boilers, the type of joint used is

(A) Butt joint with single cover plate

(B) Butt joint with double cover plate

(C) Lap joint with one ring overlapping the other

(D) Any one of the above

Correct Answer

(B) Butt joint with double cover plate

[#175] For circumferential joint in boilers, the type of joint used is

(A) Butt joint with single cover plate

(B) Butt joint with double cover plate

(C) Lap joint with one ring overlapping the other

(D) Any one of the above

Correct Answer

(C) Lap joint with one ring overlapping the other