Block or Charge?

[PG_Ref]

Originally Posted by Rob_K

A1 is guarding B1. A1 has established LGP. B1 begins their dribble towards the basket, A1 anticipates, moves latterly and has now beat them to the spot but still moving. B1 continues forward and makes contact.

1) If A1 goes down from the contact (even though they weren't standing completely still) is it a charge?

2) If B1 goes down or loses the ball, no foul?

The rule does not require that the defender be stationary upon contact. The defender is even allowed to have both feet off the floor upon contact. The defender just can't be moving forward and initiate the contact.