@OsoJr First, so you are saying him swinging his arm in the air to create enough pressure to cut down tree without breaking his arm is physics? A normal human being that can exert that much force without having the upper arm bends from their elbow, especially in his childlike body that ain't built for that or undergo a long amount of harsh training. It's ain't physics if you don't account for the air pressure and friction. If the power he produces can actually cut down a tree with a swing of a hand, then in return he will receive recoil damage from his own power collides with the air pressure. According to physics, when two objects with mass collide, they both receive forces exerted on them. Second, he deadass killed a spider from his sweat, that apparently is poison. Dude that ain't physics anymore, that is straight up chemistry, and for real I don't think chemistry can explain how his body can work like a fucking poisonous creature without magic. For a human body to produce, be immune, and store poison, you have to be a fucking god or a machine. Again, he's an old guy in a childlike body, don't tell me he spent 8 years swinging his arm, drinking and bathing in all kind of deadly poison... Because I'm sure as hell reincarnation doesn't include reusable body of his former self.
Edit: I forgot about him yelling to create a fucking sonic sound that blow up the beetle, like please, if he can do that his father, his sister, and even himself (or not since he's such a godlike creature) would all be dead. It's literally a soundwave, doesn't matter where he opens his mouth, the wave will reach anyone in the vicinity.
Edit 2: Since I decided to reread chapter one. So after he cut down the training dummy, he put it back and restored it back to normal. Please explain to me how in the world is that physics? That's literally alchemy or magic/blacksmith skill. Like dude, since my arm got chopped off, let me use "PHYSICS" to repair it....