A) An unstable particle is at rest and suddenly decays into two fragments. No external forces act on the particle or its fragments. One of the fragments has a speed of 0.70c and a mass of 6.68×10?27kg, while the other has a mass of 1.67×10?27kg. What is the speed of the less massive fragment?
B) The total annual energy consumption in the United States is about 1×1020J. How much mass would have to be converted to energy to fuel this need?