What different between collisionTraverser & collisionPus

What are they?

What do collisionTraverser and collisionPusher actually mean and what are the differences between them???

to put it in simple terms. the collision traverser detects collisoins, the pusher pushes your objects around so it does no longer intersect with the other object (if they collided).
you might want to watch the video lecture about panda’s collision system (see the documentation page)