How to get permanent force with physics

all of the physics force/movement options look like this:

while the regular force/movement choices have an option for permanent force:

what is the best way to achieve the “permanent force” option with physics? i dont want to keep adding, i want to leave it at a set value, like a variable.

Physics is like real world.
If you want an object to keep moving permanently in the real world, the only solution is outer space (set friction and gravity to 0).


the issue is, i’d like to set a force instead of adding one. i noticed this setting recently and wanted to apply it to phys. objects. for example, instead of “apply polar force to object” i want it to be “set permanent force of ___ to object” .