In the best case scenario for a gravity boost, a spacecraft approaches a planet very closely and does a U-turn around it, heading back exactly in the direction it came (see the image below). Before Collision V Tc O After Collision If the spacecraft was initially going to the right with a speed of 5 km/s, and the planet was going to the left at a speed of 9 km/s, what would be the fastest the spacecraft could be going after the U-turn, in km/s? Attach your work for full marks. Answers within 3% of the true answer will be considered correct.