If there were no gravity on the earth, would the cup break? cause

It won't break. 1) Because there is no gravity, you can't step on the earth, so you can't react. Without reaction, the strength of dropping the cup will be greatly reduced. 2) More importantly, the cup has no gravity, just like throwing a bundle of grass, it can be thrown far, but throwing a grass still can't be thrown far. That is, in the absence of gravity, the cup can't transfer the kinetic energy generated by physical energy to the cup, that is, the cup can't get energy because there is no gravity, so the cup won't break.