1. In the summer of 2010 a huge piece of ice roughly four times the size of Manhattan and 500 m thick caved off the Greenland mainland. (a) How much heat would be required to melt this iceberg (assumed to be at 0 ºC) into liquid water at 0 ºC? The annual U.S. energy consumption is 1.2 x 1020 J. (b) If all the U.S.'s energy was used to melt the ice, how many days would it take to do so?

2. Two square wires are composed differently, see the figure of their cross-sections. Wire 1 is a square wire of material A but with a circu-lar center of material C. The diameter of the circular inside is equal to the length of side of the square. The second square wire has the same cross-sectional area as the first but is entirely comprised of material A. Both wires are the same length and setup to have the same temperature difference maintained between their ends. (a) Find an expression, in terms of their thermal conductivities k, for the ratio of the heat trans-fer through wire 1 over that through wire 2. (b) If material A is Aluminum and material C is copper, find out the ratio of their heat transfers.