what is meant by elastic potential energy? Deerive an expression for the elastic potential energy of streched wire. Prove that its elasic energy density is equal to `1/2` x stress x strain

Explanation

Energy Density = `("Energy")/("Volume") =((1)/(2) (AY)/(L)x^(2))/(AL)`
`=(1)/(2)((AY x)/(L))(x)/(L)`
`=(1)/(2)(F)/(A)xx(x)/(L) " "[because Y=(FL)/(Ax)]`
`=(1)/(2)"stress" xx"strain"`