In reading newtons first law, An object at rest or in motion will remain the same unless acted on by an outside force. also known and understood in newtons 2nd is Force = mass x acceleration. An object "A" moving at a constant velocity has no acceleration therefor no force. Object "B" is stationary. When object A hits object B, B will cease to be stationary. Where did the force to move object B come from if A has no force?