1. The problem statement, all variables and given/known data A stick of dynamite blows a boulder into 4 pieces. The boulder was stationary before the explosion. After the explosion, three of the pieces have the following momenta; piece a = 10m/s West 1kg piece b = 20m/s North 2kg piece c = 10m/s East 4kg Calculate the mass of the missing piece if the magnitude of its velocity is 25m/s 2. Relevant equations Ptotal(initial)=Ptotal(final) P=mv 3. The attempt at a solution Since the boulder was not moving, its momentum is zero. The momentum of each piece is its mass x its velocity. Each piece's momentum added to each other will equal zero because momentum is conserved. So I get; 0=m1v1+m2v2+m3v3+m4v4 0=1kg(10m/s W)+2kg(20m/s N)+4kg(10m/s E)+m4(25m/s) -90kgm/s=m4(25m/s) m4=-3.6kg Now I can't have a negative mass, so what can I do to solve this?