The atomic bomb dropped on Nagasaki in 1945 used 14lbm of plutonium (Pu) that was in a subcritical state( meaning, it would not explode) at its density at ambient pressure but would go "critical" under the immense pressure ( thus increased density) created by squeezing it with conventional high explosives. The density (p) of Pu at ambient pressure is 17gram/ cm^3, Poisson's ratio (v) is 0.20 and the modulus of elasticity E is 97x10^9 Pa.
If the Pu needs to be compressed to 25g/cm^3 to explode, what strain is needed to obtain this density? [strain = (delta Length)/Length)]?