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)`]

Explanation

Let l be the maximum length of the wire that can hang vertically without getting broken.
Mass of the wire m= cross sectional area `(A)xx` length (l)`xx` density `(rho)`
Weight of the wiere `mg=A l rhog`
This is equal to the maximum force the the wire can withstand.
`:.` BReaking stress `=(l A rho g)/A=l rho g`
or `7.5xx10^(8)=lxx2.7xx980`
`impliesl=(7.5xx10^(8))/(2.7xx980)=2.834xx10^(5)cm=2.83km`