- #1

- 290

- 1

I know that E

_{a}+ E

_{b}= Mc

^{2}, from conservation of energy. But I'm pretty confused about signs in the conservation of momentum equation, and I've actually seen two versions!

p

_{a}+ p

_{b}= 0, so

p

_{a}= - p

_{b}.

But I've also seen p

_{a}= p

_{b}! I know one is magnitudes and the other takes account of directions. Both are right, but which applies for the situation described above? As in, don't they conflict?