Mechanical Engineering - Strength of Materials - Discussion

Discussion Forum : Strength of Materials - Section 7 (Q.No. 19)
19.
Two solid shafts 'A' and 'B' are made of the same material. The shaft 'A' is of 50 mm diameter and shaft 'B' is of 100 mm diameter. The strength of shaft 'B' is __________ as that of shaft A.
one-half
double
four times
eight times
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
11 comments Page 1 of 2.

MUHAMMAD NABI said:   4 years ago
As we know the strength of the shaft is measured by polar modulus.

Polor modulus = j/r.

Here solid shaft is given so for the solid shaft.

π/16 (d) ^3.

Now as db =100.
And da=50.

So.

π/16 (db) ^3 divide by pi/16 (da) ^3.

After a cancellation we get.

(db/da) ^3.
= (100/50) ^3.

= (2) ^3.

=8.

Roshan said:   10 years ago
Here torque formula is used to compare their strength. As we know that torque is directly proportional to d^3 of the shaft.

Abreeque said:   9 years ago
M/sigma = z, and z = i/y.
= pi * d^4/64/d/2,
= pi * d^3/32,
So, z1/z2 = d1^3/d2^3.
= (50/100)^3
= (1/2)^3 = 1/8.

Satyabrata said:   8 years ago
Yes, torque solid shaft formula is used to get the answer.

Needo said:   4 years ago
@Yatheesh,

It's of the shaft, So option B is right.

Raheem said:   1 decade ago
Any can explain how it will be answer D?

NwosuKC said:   9 years ago
Not clear, please explain in detail.

Naresh said:   8 years ago
Thanks @Aabreeque and @Roshan.

Krunal degamadiya said:   8 years ago
It should be 1/8 times.

Juju said:   1 decade ago
Can any one explain?


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