Let's say 10 kg block is sliding on a frictionless surface at a constant velocity, thus its acceleration is 0.
According to Newton's second law of motion, the force acting on the block is 0:
$a = 0$
$F = ma$
So let's say that block slid into a motionless block on the same surface, the motionless block would move.
Wouldn't the first block need force to be able to move the initially motionless block? I understand that it has energy due its constant velocity, but wouldn't it be its force that causes the displacement?