Acooper object that can be modeled as cube with 10 cm edges is soaking at uniform temperature of 260 c. it was suddenly placed in an environment maintained at 35 c and having heat transfer coefficient h=20 w/m2. c. the properties of the copper are as follows: rho = 8900 kg/m^3, cp=0.38 kj/kg. °c, and k=370 w/m-c. a)- calculate the time required for the center temperature to reach 90°c. b)-calculate the total heat transfer over the time period required for the center temperature to become 90°c.