-28 kg, An unstable particle at rest spontaneously breaks into two fragments of unequal mass. The mass of the first fragment is 2.80 x 10 and that of the other is 1.76 × 10-27 kg. If the lighter...

Extracted text: -28 kg, An unstable particle at rest spontaneously breaks into two fragments of unequal mass. The mass of the first fragment is 2.80 x 10 and that of the other is 1.76 × 10-27 kg. If the lighter fragment has a speed of 0.864c after the breakup, what is the speed of the heavier fragment? (Assume the speeds are measured in a frame at rest with respect to the original particle.)