Where did you get that question? You said 'You know that you're moving'. How do you know that when there's nothing outside the spaceship to refer to? For all you know, you could be stationary or moving at a constant velocity.
You need no physics knowledge to do mechanics. As long as you are aware of the forces on an object, then you should be fine.
Stop making that up as an excuse for yourself, you won't do well that way. Keep a positive attitude.