(a) At the time of this books printing, the U.S. national debt is about $ trillion. If payments were made at the rate of $ per second, how many years would it take to pay off the debt, assuming no interest were charged? (b) A dollar bill is about long. How many dollar bills attached end to end would it take to reach the Moon? The front end papers give the EarthMoon distance. Note: Before doing these calculations, try to guess at the answers. You may be very surprised.