Mechanical Engineering - Strength of Materials - Discussion

Discussion Forum : Strength of Materials - Section 8 (Q.No. 36)
36.
The rectangular beam 'A ' has length l, width b and depth d. Another beam 'B' has the same width and depth but length is double that of 'A'. The elastic strength of beam 'B' will be __________ as compared to beam A.
same
one-half
one-fourth
one-eighth
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
38 comments Page 2 of 4.

Anurup said:   8 years ago
I will also go with the 1st option i.e, same. Because elastic strength means section modulus and it does not depend upon length.

Apcivilian said:   9 years ago
The right answer is A because elastic strength Z. Doesn't depend on Length.

z = bd2/6.

Same is answer.

Abhishek said:   10 years ago
If length, width are remains same and depth is double that of A then what's the elastic strength of B?

Ravinder Singh said:   8 years ago
If length increase moment increase if moment double bending becomes double and strength becomes half.

Prasad said:   7 years ago
(PL/AE)a * (PL/AE)b.

Now increase the length by 2 in b.
(PL/AE)a * (2PL/AE)b.
(a/b)=(1/2),
b = 2a.

Usha said:   6 years ago
σ1= M/z1=w*l/z,
σ2= M/z2=w*(2*l,)
Z1=z2 as b,d are same.

So, σ1/σ2 = 1/2.

Anand said:   1 decade ago
Strength of beam can be calculated by formula R = 1.5PL/bh^2.

Hence right answer.

Pranavi said:   8 years ago
Flexural strength (σ)= (3FL)/(2*bd^2), what about this? Please explain.

Shubham said:   5 years ago
@Usha.

Elastic strength of beam with double Length will be double not half.

Vicky said:   8 years ago
Can Anyone explain What Is Elastic Strength?

And how can we find it?


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