Question

The breaking stress of aluminimum is `7.5xx10^(8)` dyne `cm^(-2)` find the greatest length of aluminium wire that can hang vertically without breaking density of aluminimum is `2.7gcmL^(-3)` [given `g=980cms^(-2)`]

Answer 1

Let l be the greatest length of the wire that can hang vertically without breaking mass of wire `m="crosds"-"section"` area (A) `xx` length (l) `xx` density `(rho)`, weight of wire =mg=`Alrhog`
This is equal to the maximum force that the wire can withstand.
`therefore"Breaking stress"=(lArhog)/(A)=lrhogimplies7.5xx10^(8)=lxx2.7xx980`
`impliesl=(7.5xx10^(8))/(2.7xx980)cm =2.834xx10^(5)cm=2.834cm`