Question

Volume question

Answer 1

Okay so the answer is B and we can work it out using the youngs modulus.
But what's wrong in this working.
Volume before compression = Volume after compression
Volume before compression = l³
Volume after compression = Δl x l²
l³ = Δl x l²
l = Δl
l is proportional to Δl

Answer 2

@vishweshshrimali5

Answer 3

Don't forget the change in lateral length... recall poisson's ratio

Answer 4

Okay wait I think it should be
l³ = (l-Δl) x (l+√Δl)²

Answer 5

@FaiqRaees with this compression when the length of metal cube are shorted so then the width of metal cube will be larged - i think it so - yes ?

Answer 6

Yeah I edited the formula

Answer 7

l³ = (l-Δl) x (l+√Δl)²

Answer 8

@jhonyy9 But the answer is still not coming

Answer 9

yes i see it same but i think that bc. the length l not is same with the width l can you sign it with different letter please ?

Answer 10

Not its a cube all lengths are same

Answer 11

and when you write delta thie mean the initiale length l_i minus the length after compression let being l_2
- try sign the width same

Answer 12

so bc delta wan meaning the modification of cube after compression

Answer 13

Oh but if i introduce more coefficients then we can't derive a relation between l and delta l

Answer 14

yes i understand you but now i remember that in same cases we can using integrale of ... or somthing in this way - do you know it ?

Answer 15

I know integration but how are we suppose to use that

Answer 16

sorry this was to much years ago ,try other helper ,suppose @hartnn

Answer 17

@hartnn I mentioned at the start that we can solve the question using youngs modulus. I wanted to know what's wrong in this working.
Volume before compression = Volume after compression
Volume before compression = l³
Volume after compression = Δl x l²
l³ = Δl x l²
l = Δl
l is proportional to Δl

Answer 18

@ganeshie8