No kid should ever have things thrown at them. No kid should be hit or live in fear of her own father. I’m worried that at some point your dad won’t know how to stop and you (or your mother or sister) will be really, really hurt. So – yes, your dad does have a big problem but it would probably be dangerous for you to be the one to tell him so. I have no reason to think that he would have a calm discussion with you about his behavior.
Unfortunately, it sounds like your mother is as afraid of him as you are. Instead of protecting you girls, she breaks into tears. She needs some help too. It might help if you, your mom, and your sister had a serious talk together about what to do. You can’t change your dad. He isn’t interested in changing. But it’s possible you could all get away to a safe place until he gets himself into some counseling and learns how to control himself.
Support your mom in checking into options for practical help and support. There is a 24-hour crisis line in your city for families like yours. Also check out this website. Everyone in your family deserves so much better.
I wish you well.