Centrifugal force is also used to achieve the concept called artificial gravity, which is the reason why characters in Star Trek walk around like normal in their starships.
Some sci-fi has cylindrical ships or space stations spun for gravity, but in Star Trek they have "gravity plating", so the ships don't have to spin. A convenient plot device to cover the fact that they didn't have the budget to shoot every episode aboard the vomit comet.