A cannon of mass 6.31 x 103 kg is rigidly bolted to the earth so it can recoil only by a negligible amount. The cannon fires a 71.1-kg shell horizontally with an initial velocity of 528 m/s. Suppose the cannon is then unbolted from the earth, and no external force hinders its recoil. What would be the velocity of a shell fired from this loose cannon? (Hint: In both cases assume that the burning gunpowder imparts the same kinetic energy to the system.)