Question

An object at rest explodes into three fragments. The figure shows the momentum vectors of two of the fragments:

vector P1 is directed along the px axis and has a magnitude of 74.0 kg m/s.
vector P2 is at an angle of 300.° measured counterclockwise from the positive px axis and has a magnitude of 26.0 kg m/s.
What are the px and py components of the momentum of the third fragment?

Answer 1

If it was at rest and there is no EXTERNAL force then:
total x momentum = 0
total y momentum = 0