object a slams into object b in space what will be object b's speed be after the collision what about object a

Question

The mass of both objects are exactly the same

Answer 1

It depends on whether the objects are completely elastic, completely inelastic, or somewhere in between. And also, did they hit square and were the velocities both on the same line or did they get deflected at a new angle. I'll assume they hit square and their velocities were on a line - like they were on a track.

Elastic:
Momentum before = momentum after
Ma*Va + Ma*Vb = Ma*Vb + Mb*Va

Inelastic:
M*Va + M*Vb = 2M(Va+Vb)/2