How do I motivate myself?

I cant just decide to sit down and do work and get stuff done, Ive never been able to work like that. So... what am I supposed to do? My parents are always threatening to punish me for not doing my work and actively are punishing me for not doing work but honestly? I don't care. They've been threatening and punishing my entire life, im not scared of the punishments and I know I'll survive. Ground me, take all my shit, scream at me, hit me, I couldn't care less it doesnt get my work done it only puts me in a bad mood and if anything makes me MORE reluctant to do my work. So how do I get myself to do my work? Because I know I need to do it but can't figure out how