Relativity

A satellite is at rest in space when  destroyed by a hostile alien space ship.  One piece that is 100 kg floats away at a speed of 0.80C.  Another piece floats away with a speed of 0.90C away from the explosion in the opposite direction.  What is the mass of the piece that flew away in traveling at 0.90C.  Determine this two ways.  1) by including special relativity  2) by ignoring special relativity

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