A steel wire of 1mm diameter and of length 1m is stretched by applying force of 10N. If the increase in length is 0.064mm, find (i) the stress, (ii) the strain and (iii) the Young's modulus of the wire.

Explanation

`r = 0.5 xx 10^(-3) m, L = 1m`
`F = 10N, e = 0.064 xx 10^(-3) m`
i) stress ` = F/A = (F)/(pir^2) = (10)/(pi (0.5 xx 10^(-3))^2) = 1.273 xx 10^7 Nm^(-2)`
ii) stress ` = e/L = (0.064 xx 10^(-3))/(1) = 0.064 xx 10^(-3)`
iii) Y = stress/strain ` = (1.273 xx 10^7)/(0.064 xx 10^(-3)) = 1.989 xx 10^11 Nm^(-2)`