An unstable particle at rest breaks up into two fragments of unequal mass. The mass of the lighter fragment is equal to 2.40 x 10-28 kg and that of the heavier fragment is 1.67 x 10-27 kg. If the lighter fragment has a speed of 0.893 c after the breakup, what is the speed of the heavier fragment?
Please show work and formulas so i can practice problem.