Can someone point my mistake? Not getting the ans .

Question for you : what is the same and what is different in each of the sections of the composite rod?

 

Why did you not add this to your previous thread question?

Please ask a mod to combine the two threads.

 

Edit for those who would like to see the original question

 

Edited March 25, 20169 yr by studiot

I think you got it wrong. The other question on young modulus and this one are separate.

Sorry but your originals are such a mess I don't know what I got right or wrong, but you posted the following yesterday

 

 

Thanku guys thanku so much. Yes stringjunky il make sure to rotate them next time.

 

If you can't get the page all in the other way round copy it out yourself so it fits your phone.

 

Now how about answering the question I asked, which is relevent to the question you posted in the other thread, and I reposted properly here.

Edited March 25, 20169 yr by studiot

Im so sorrrrry for the rotation issues. Still cant figure that out however il sutely do something about that .....

Ans to your question :

Cross sectional area is same . the young modulus are different

Is that all?

 

What about

 

the tensile force

The stress

The strain

 

?

Strain must be same force applied is same . Stress is alsoo same .... and then tensile force is also same

And what is your definition of young's modulus?

Youngs = stress / strain .. i think i have to calculate the stres and strain of plastic and nylon individually.

 

Youngs = stress / strain .. i think i have to calculate the stres and strain of plastic and nylon individually.

 

 

Now we are getting somewhere.

 

if the youngs moduli (note the plural) are different, how can the stress and strain both be the same?

 

Do you think the stress or the strain or both are different?

Kindly kindlykindly can u refer to my orinal post . I edited that gave my solution (although the pic is tilted sorry for that )

Strain is different...... stresss is same

 

 

studiot post 2

Now how about answering the question I asked, which is relevent to the question you posted in the other thread, and I reposted properly here.

 

 

I have only been talking about the question from your other post, which I see now is different from the original question in this thread.

 

I can only deal with one subject at a time.

Edited March 25, 20169 yr by studiot

Lets just stick to other thread the one about which we were just talking .

 

So the strain changes but the stress doesnt change.....

Lets just stick to other thread the one about which we were just talking .

 

So the strain changes but the stress doesnt change.....

 

In the case of the composite rod, pulled in tension at both ends, yes this is correct.

 

So can you now calculate the strain for both pieces and complete the question, including the max stress?

Yesssssss this was sooooo helpful. .. thanku soo soo much

You should have something like this

 

Let x = strain in grp section

 

Let y = strain in nylon section

 

Then (x + y)* 10^-3 = 3 * 10^-3, where x and y are in mm

 

Stress in grp = stress in nylon

 

E_grp * x * 10^-3 = E_nylon * y* 10^-3

 

E_grp * x = E_nylon * (3-x)

 

I'm sure you can finish the arithmetic.

Edited March 26, 20169 yr by studiot

Yes I got it now. Thanku so much!!!!

Done with the arithmetic tooo got the ans ... now may I ask for one more favour .... I use my cellphone to take the pictures and I post them here .... initially the pictures are straight but whenever I add them here they automatically get rotated .. plus cant find any rotation key.... if u could help me solve this problem too ... thanks

 

studiot

Let x = strain in grp section

 

Let y = strain in nylon section

 

First an apology.

These, of course, should have be x and y are the extensions, not the strain.

However the math was correct and this oversight obviously didn't bother you.

 

well done.

 

 

Now for your second question.

 

I'm sorry I have no experience with cellphone cameras so can't help with the rotation/posting.

Try asking one of the younger members.

I would say, however, that if you can, greyscale saves memory and transmission bytes, when colour is not needed.

 

Here are your rotated and greyed images plus my working of the problem.

 

Note I have used the radii not the diameters, since this avoids some extra fractions.

I suspect you have got some (one) of the fractions the wrong way up, so the fewer the better.

 

Once again the problem solution depends upon the force being the same in both.

Thanks a lot a lot. First forum which is actually helping me...... ihave tons of questions il try asking someone to help me with the rotating. ...

You have been reallly helpful