1. Air in a closed system undergoes an internally-reversible expansion with constant pressure from T₁ = 1000K to T2 = 1500K. Calculate (a) the work and (b) the heat transfer involved in kJ/kg, assuming constant specific heats evaluated at 300K.

1. Suppose identical solid spheres are distributed through space in such a way that their centers are lie on the points of a lattice, and spheres on neighboring points just touch without overlapping. (Such an arrangement of spheres is called a close-packing arrangement.) Assuming that the spheres have unit density, show that the density of a set of close-packed spheres on each of the four structures (the "packing fraction") is: fcc: bcc: √√2/6=0.74 √√3/8=0.68 SC: π/6=0.52 √√3/16=0.34 diamond:

I have been working on this Solid Mech problem for a while and have gottem nowhere we are supposed to be finding the modulus of elasticity for a set of data (attached). I have made an excel sheet from this to finda stress strain graph. I understand how the modulus of elasticity is (E = (delta stress)/(delta strain)) but I cannot find the propotional limit that I need to find delta stress and delta strain