Py (kg m/s) 2- PI P2 -2 Px (kg m/s) 2 P3 A firecracker is initially at rest. It then explodes into four fragments. The momentum vectors of three fragments are shown in the diagram. Which vector best represents the momentum of the fourth fragment after the explosion? O p4,x = 1.0 kg m/s ; p4,y = 1.0 kg m/s O p4,x = -1.0 kg m/s ; p4,y = 1.0 kg m/s O p4,x = -1.0 kg m/s ; p4,y = -1.0 kg m/s O p4,x = 1.0 kg m/s ; p4,y = -1.0 kg m/s O p4,x = 2.0 kg m/s ; p4,y = -1.0 kg m/s O p4,x = -2.0 kg m/s ; p4,y =-1.0 kg m/s p4,x = 2.0 kg m/s ; p4,y = 1.0 kg m/s O p4,x = 2.0 kg m/s ; p4,y = 2.0 kg m/s O p4,x = -2.0 kg m/s ; p4,y = 1.0 kg m/s 1 pts