I think it depends. "Beating" is rather general and refers to physically striking a person. This could be with fists, open hands or even an object such as a belt. However, "whipping" is more specific and refers to striking someone with a whip or similar object. So if the person was hit with an object similar to a whip, both can be used if not 'beating' would be better. Sometime people use them interchangeably but they are a little different.

I believe beating would actually be more appropriate in this sentence than whipping is. The usual phrases are "to get whipped" and to "take a beating", both meaning that the subject lost a battle/game/fight badly.