1. Blackbody! (10 points) A blackened, solid copper sphere that has a radius equal to 4.0 cm hangs in an evacuated enclosure whose walls have a temperature of 20 EC. If the sphere is initially at 0 \"C find the initial rate at which its temperature changes, assuming that heat is transferred by radiation onl},r and the sphere is a perfect blackbody 2. Gased! (10 points) An ideal has undergoes a process during which PW = constant and the volume of the gas decreases. Does its temperature increase, decrease, or remain the same? Explain. 3. Melting! (10 points]I A lead bullet initially at 30 C just melts upon striking a target. Assuming that all of the initial kinetic energy is converted into internal energy, what is the impact speed of the bullet? The following are the properties of lead: melts at 600 K, heat capacity is 0.128 Flag, the latent heat of vaporization is 858 Eahe latent heat of fusion is 24.7 11%. 4. The diesel! (10 points) Calculate the efficiency of the diesel engine cycle shown on page 4f 9 of your Enthropy study guide. Make sure that the efficiency is in terms of V1, V2, V3, V4, where V,- are the volumes at points 1, 2,3, 4 marked in the diesel engine's PV diagram