Should i forgive him?

Every day and i get home from school, thinking 'hes gonna explode again' Dad has always had some kind of issue, because i remember when i was being screamed by at him and he threatened to lock me in my room along with my big sister izzy: I cant remember what it was over, something to do with a vase, i think. He sometimes locks us in the house, nd hits us hard, but lies about it to mum, saying that we've been 'naughty' and that he didn't touch us. But what really scares me is what he does to mum: Once, he banged a wok on her heel, luckily mum was okay but what was it over: The meals being too soggy. I hate what he does to Izzy, my big sister also: Sometimes for a cheap thrill he just randomly shouts at iz, for 'fun'. To think when i was younger....i used to trust him....but now all i do is hate him....All he ever does is fight us...i get so scared i just lock myself in my room and cry, and when mums out, that's when he makes it the most hard, i can recall him shouting at me because i was on the computer why it was doing a weird recalibrating thing, and he chased me into my room and slapped me....and when mum came back and i told him what he did (Dad calls t snitching) dad says that he didn't touch me. But he always rying to make up with us when he feels guilty and i always say "As long as you wont do it again" but i know he does...........What do i do, i cant tell anyone at school because i think they might tell, and then im in trouble........I know he'll never severly hurt me and that im safe but i feel like i dont belong...