Hey there! I work on the UEFN documentation team, hopefully, my suggestions are helpful 
The best way to simulate physics atm is using the Prop Mover Device. You could use a trigger that a player steps on to trigger the prop mover to move the prop at a speed you determine, possibly simulating physics. Not sure how smooth this would be, I haven’t tried this out myself yet.
If the Prop Mover doesn’t have the type of functionality you need, you can request a physics feature for UEFN in this channel: Feedback & Requests - Epic Developer Community Forums
There are some settings in the Island Settings device that provide a way for you to alter the gravity as well, but I’m not sure this would help you achieve what you’re looking to do.