Two cars collide inelastically and stick together after the collision. Before the collision, the magnitudes of their momenta are P1 and P2 . After the collision, what is the magnitude of their combined momentum?
a) P1+P2
b) P1-P2
c) P2-P1
d) (P1P2)^(1/2)
e) (1/2)(P1+P2)
f) (P1+P2)^(1/2)