Unit FM $5. Suppose you could start an object moving and then arrange for absolutely no forces to act on it. How would it move from then on? To help you think about this question, consider the following: Suppose a spacecraft is at rest in deep space, far from any stars or planets, so that no form of friction or gravity is acting on it. The main engine, at the rear of the spacecraft, is fired for a period of 2 seconds (to start the spacecraft moving) and is then shut off. What do you think the motion of the spacecraft would be like after the engine is shut off? Explain your reasoning