A49.0-kg body is moving in the direction of the positive x axis with a speed of 268 m/s when, owing to an internal explosion, it breaks into three pieces. one part, whose mass is 9.5 kg, moves away from the point of explosion with a speed of 466 m/s along the positive y axis. a second fragment, whose mass is 5.0 kg, moves away from the point of explosion with a speed of 440 m/s along the negative x axis. what is the speed of the third fragment? ignore effects due to gravity.