A spacecraft is to the right of an asteroid. The spacecraft exerts a gravitational force of 800 N on the asteroid to the right. At the same time, the spacecraft's engine produces a thrust of 500 N on the spacecraft to the right. The spacecraft is initially stationary. Ignore all other forces.
State the size and direction of the gravitational force exerted by the asteroid on the spacecraft.
Explain why the two gravitational forces in the interaction do not cancel when considering the motion of the spacecraft.
Calculate the resultant horizontal force on the spacecraft and state what happens to its motion.