Spheres with 40-mm diameter are heated to a uniform temperature of 400°c and then suddenly removed form the over and placed in a forced air bath operating at 25°c with a convection coefficient of 300 w/m^2 k on the sphere surfaces. the thermophysical properties of the sphere material are p=3000 kg/m^3 c=850j/kgk, and k=15 w/m k. 1)- how long must the spheres remain in the air bath for 80% of the thermal energy to be removed? 2)- once 80% of the thermal energy is removed, the spheres are then placed in an adiabatic enclosure that prevents any more heat transfer between the spheres and their surroundings what uniform temperature will the spheres eventually reach?