A substance breaks down under a stress of `10^5` Pa. If the density of the substance is `2xx10^3kg//m^3`, find the minimum length of the wire made of this substance which will break under its own weight `(g=10m//s)`.

Options

A. 10 m
B. 2.5 m
C. 4 m
D. 5 m

Answer

D

Explanation

Stress at B is maximum, so the wire will break first at B if stress here becomes `10^5Pa`:
`(mg)/(A)=10^5`
`implies(ALrhog)/(A)=10^5impliesL=(10^5)/(rhog)=5m`