A load of 10 kg is suspended by a metal wire 3 m long and having a cross sectional area `4mm^2`. Find a. the stress b. the strain and c. the elongation. Young modulus of the metal is`2.0xx10^11Nm^-2`

Answer

A, B, C, D

Explanation

`m=0kg`
`L=2m`
`A=4mm^2=4x10^-6m^2`
`y=2xx10^11N/m^2`
a. `F=mg`
`Stress=F/A`
`=2.5xx10^7N/m^2`

b. `Strain=(Delta L)/L`
`Y=(FL)/(ADeltaL)`
`Delta L=F/(YA)`
`=(10xx10)/(2xx10^11xx4xx10^-6)`
`=1.25xx10^-3N/m^2`
`rarr 1.25xx10^-4xx3=3.75xx10^-4m`