The maximum load that may be applied to a mild steel wire is 7 kg wt. If the radius of the wire is 0.2 mm, find the maximum elastic strain permitted . `[ Y = 2xx 10^(11) N//m^(2)]`

Explanation

Data : ` W_(max) = 7 " kg wt" = 7 xx 9.8 N, r = 0.2 mm = 2 xx 10^(-4) ` m
` Y = 2xx 10^(11) N//m^(2) , g = 9.8 m//s^(2)`
` Y = ("stress")/("strain")`
The maximum elastic strain = maximum elastic stress /Y
`(W_(max)//A)/Y = (W_(max))/(pir^(2)Y)`
` (7 xx 9.8)/(3.142 (2xx 10^(-4))^(2) (2xx10)^(11))`
` (68.6 xx 10^(-3))/(3.142 xx 8) = 2.729 xx 10^(-3) or 0.2729 %`