How to get ball direction/velocity in Atari Pong?

[pedrohpf]

Hello, I was checking the ram annotations for Pong and it seems like only the score and position of the players and ball is known from the ram, my thinking was that they also stored ball direction in order to make it move frame by frame.

Are those annotations just missing from that page or do they do that in some other way that does not use the ram?