[pixl97]

>do you need to understand physics and biology to know how the movement and speed of a hand interacting wi

In one sense, no because we get this programmed in for free by our ancient biology. But do note that it did not just pop up full formed and took quntillions of complex interactions over eons of time to get to the point it is now. This is why making robots that behave like biological entities is insanely hard, evolution has spent an epic fuckton of compute on the problem already.

Now, if you're building human like robots, then yes, you need to understand all the above.