A wire of length 0.89 m and cross-sectional area 1.7 cm2 is stretched elastically by an amount 1.2 cm. By Hooke’s law, the restoring force is $−k\Delta L$.
Calculate the work done in stretching this wire by an amount $\Delta L$. Young's modulus is 1.3 $\times$ 1010 N/m2
I don't really know where to start.