I've never thrown a ball and had it continue to accelerate after leaving my hand. Are you sure about that?
100%. You live in a world with an atmosphere. There is a thing called air. That air causes resistance, which causes friction, which causes deceleration.
Have you ever thrown a ball in a complete vacuum? No, so of course it doesn't continue to accelerate.
Air resistance certainly exists in FE.
If you accelerate an object, i.e. throw a ball and there's nothing resisting that acceleration, will the ball continue its acceleration constantly?
Theoretically, without balancing forces, yes. However, no matter how fast you throw the ball, the Earth will catch up to it in the same manner as in RE: a constant acceleration of 9.8m/s
2. Taking interference into account, the ball will lose energy due to non-conservative interactions.
Nothing, you've already imparted acceleration to have it go from V=0 to V=V. That acceleration will never dampen, or dissipate, as long as there is no outside force acting on it. Which means that it will constantly accelerate.
What about it?