A helmet has an open cell polystyrene foam liner that is design to absorb the kinetic energy from an impact. The Foam has a relative density of 10% and the young module of the solid polystyrene that the foam is 1.5Gpa. How much energy per volume in J/m^3, can the foam absorb if it is loaded in uni axial compression to uni axial compression to strain 80%, please assume that C1=1.0 and C2=0.05