(Solved) Physics: One object sinks, another floats.

Hi everyone,

In physics, how would you approach it if you wanted to have two objects with two different gravitation in the game at the same time? For example, one is a rock that is heavy and falls, and a balloon that is light and will float upwards.

Appreciate any help on this. thanks everyone!

Found a solution after some testing. For those who are interested. I applied a force every tick to the object that needs to float. Not sure if it's the most efficient way, but it works for now.