A unifrom steel rod of cross section `5mm^(2)` is heated from ` 0^(@)C` to`25^(@)C`. Find the force which must be exerted to prevent it from expanding. Also, find the energy stored per unit volume of the rod.

Explanation

Given : `A = 5 mm^(2)=5xx10^(-6)m^(2), DeltaT=(25-0)^(@)C=25^@C,`
`alpha_("steel")=12xx10^(-6)//^@C, Y_("steel")xxDeltaTxxA`
`= 20xx10^(10)xx12xx10^(-6)xx25xx5xx10^(-6)`
`30000xx10^(10)xx10^(-12)=300N`
Strain`=alpha_("steel")xxDeltaT` ltbtgt `=12xx10^(-6)xx25`
`=300xx10^(-6)xx25`
`=330xx10^(-6)=3xx10^(-4)`.