A significant obstacle in the design of atomic weapons is theso-called delta phase instability (a type of mixed dislocation) inPu-239. This is the problem: We wish to construct a sphericalatomic bomb core out of pure delta phase (f.c.c.) Pu-239. A deltaphase instability has shear strain θ = er and shearstress T = (sinr)/2πr2 where r is in cm, θ isunit less, and T is in units of N/cm2 . Assume that forthe purposes of elastic energy calculations ro = 0, andthat there is a single instability. The density of Pu-239 is listedas 19.8 gm/cc. Compute the excess elastic energy E associated withthis instability. Be very careful with units and dimensions.