How to get electrical force in AC/DC module

Hi, everyone!

I am building a model in COMSOL. In this module, I build a container full of dielectric, like water. And I will put two electrodes on the opposite side, one 5V, and the other 0V. And I put a metal ball in the middle. Then I calculate the model by using AC,DC current, and get the electric field in the area.

Then, the question is how can I get the electrical force on the metal ball?

Thanks in advance.

Ruochen