Physics
posted by Joan .
Explosives are used to blow a rock apart. The explosion blows the rock into three fragments. Two fragments go off at a 76 degree angle to each othera 6.2 kg piece at 26.7 m/s and a 5.5 kg piece at 23.3 m/s. Calculate the speed of the third piece, if it has a mass of 3.2 kg.

The total momentum of all three fragments must be zero. Add the momenta of the two fragments for which data are provided. The third fragment will have momentum equal and opposite to that. You can gets its speed by dividing its momentum by its mass.