Question

A vertical brass rod of circular section is loaded by placing a 5kg weight on top of it. If it's length is 50cm, it's radius of cross section 1cm and the young modulus of the material is 3.5power 19

Answer 1

a) contraction in rod is given by

$\Delta l=\frac{mgl}{\pi r^2Y}$

Putting value of all variable and constants according to data of question

$\Delta l= \frac{5\times9.8\times50\times10^{-2}}{3.14\times1\times10^{-4}\times3.5\times10^{10}}$

$\Delta l=22.29\times10^{-7}m$

b) stored energy is given

$U=\frac{mg\Delta l}{2}$

$U=\frac{5\times9.8\times22.29\times10^{-7} }{2}$

$U=5.46\times10^{-5} J$