As part of an interview for a summer job with the Coast Guard, you are asked to help determine the search area for two sunken sh
ips by calculating their velocity just after they collided. According to the last radio transmission from the 40,000-ton luxury liner, the Hedonist, it was going due west at a speed of 20 knots in calm seas through a rare fog just before it was struck broadside by the 60,000-ton freighter, the Ironhorse, which was traveling north at 10 knots. The transmission also noted that when the freighter's bow pierced the hull of the liner, the two ships stuck together and sank together.
The gravitational force is inversely proportional to the square of the distance between their centers. So the force is greatest when the distance is zero.