Que: Cold working produces the following effect (Engg services 2003)

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1. Stresses are set up in the metals. 2. Grain structure gets distorted. 3. Strength and hardness of the metal are decreased. 4. Surface...

Que: A tapering bar (diameters of end sections being d1 and d2) and a bar of uniform cross section d have the same length and are subjected to the same axial pull. both the bars will have the same extension if d is equal to (Engg Services-1998)

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(a) d1 + d2 / 2 (b) (c)      (d)                                    Ans: (b) Explanation:  E = Stress / Strain = WL /  ΔL  A For a...

Que: Two tapering bars of the same material are subjected to tensile load P. The larger diameter of each of the bar id D. The diameter of the bar A at its small end is D/2 and bar B is D/3. If both the bar are the same length, then what is the ratio of elongation of bar A to bar B. (Engg Services-2006)

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(a) 3 : 2 (b) 2 : 3 (c) 4 : 9 (d) 1 : 3 Ans: (b) Explanation:   For a  tapering   rod, ΔL = 4WL / π d1 d2 E ΔL for A bar = 4WL / (...

Que: Two identical circular rod of the same diameter and same length are subjected to same magnitude of axial tensile force. One of the rod is made out of mild steel having the modulus of elasticity of 206 Gpa. The other rod is made out of cast iron having modulus of elasticity of 100 Gpa. Both the material are homogeneous and isotropic and the axial force causes the same amount of uniform stress in them. if the stresses developed are within the proportional limit of respective materials, then which of the following statement are correct (Gate-2007)

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(a) Both rods elongate by the same amount (b) Mild steel rod elongates more than Cast iron rod (c) Cast iron rod elongates more than Mild...

Que: The total area under the stress-strain curve of a mild steel specimen tested upto failure under tension is a measure of its (Gate-2002)

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(a) Breaking Strength (b) Toughness (c) Hardness (d) Stiffness Ans: (b) Explanation:  Breaking strength is the maximum  stress  that ...

Engineering Mechanics example (Gate-2005)

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Que: A time variation of the position of a particle in rectilinear motion is given by   x = 2t 3 + t 2 + 2t  If v is the velocity and a i...

Que: a car moving with uniform acceleration covers 450 m in a 5 second interval, and covers 700 m in the next 5 second interval. the acceleration of the car is (Gate-98)

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(a) 7  m/s 2 (b) 10  m/s 2 (c) 25  m/s 2 (d) 50  m/s 2 Ans: (b) Explanation: Here  u = initial velocity v = final velocity a = acc...