Oh, it's tricky. It means Zaids' father hits Amr.

Zaid beats his father Amra

It means Zaids' father is hitting Amr. but this is a very advanced trick. زيد يضربُ أباه عمرا means Zaids is hitting his father Omar.

It seems so strange for anyone to hit his/her father! Whatever, the verb "يضرب" here is closer to continues present than to simple one, so it's "Zaid is hitting his father, Omar." If you'd like to accept a correction, your sentence should be "زيد يضرب أباه عمرًا" because "أب" is one of the five names in Arabic that their final latter form depends on their position in the sentence; here "father" is object so it takes " ا " instead of " و " for its final latter. Good luck!

Zaid beats his father Amra