Mechanical Engineering - Strength of Materials - Discussion

Discussion Forum : Strength of Materials - Section 3 (Q.No. 25)
25.
Two bars of different materials and same size are subjected to the same tensile force. If the bars have unit elongation in the ratio of 2:5, then the ratio of modulus of elasticity of the two materials will be
2:5
5:2
4:3
3:4
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
12 comments Page 1 of 2.

Nauman Akram said:   5 years ago
&l=pl/AE.
E1=pl/2A.
E2=pl/5A.
E1/E2 =pl/2A/pl/5A.
E1/E2= 5/2.
E1/E2 = 5: 2.
(3)

AMAL said:   10 years ago
e(strain) = delta l(change in length)/original length.

Strain = stress/E.

Strain = Change in length (elongation) is inversely proportional to E.

That is 5:2.
(1)

Sri said:   9 years ago
But they are comparing to two bars na.

Swap said:   9 years ago
Yes, right. How is that possible?

Rushi said:   9 years ago
Delta L = PL/AE.

Let, delta L a/deltaLb = 2/5.

(PL/AE) a* (AE/PL) = 2/5.

Eb/Ea = 2/5.

Ea/Eb = 5/2.

ATUL said:   9 years ago
E1 = E2.
PL/A $L1= PL/A $L2
1/$L1= 1/ $L2
1/2= 1/5
THEREFORE 5/2.

Nayan said:   7 years ago
Thanks @Atul.

Abhay said:   7 years ago
E1=1/2.
E2=1/5.

δ = E1/E2,
= 5/2,
OR 5:2.

Princess said:   7 years ago
δL is inversely proportional to E.

So δL is 2/5 and hence E becomes 1/ (2/5) = 5/2.

Sourava said:   6 years ago
Elongation, e1 = PL/AE1 (for 1st material).
or, E1 = PL/Ae1.
e2 = PL/AE2 (for 2nd material).
or, E2 = PL/Ae2.
Now, E1/E2 = (PL/Ae1)/(PL/Ae2).
= e2/e1.
= 1/(e1/e2).
Hence, the ratio of modulus of elasticity of the two material is 5:2.


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