Suppose you are at the beach, standing at the edge of the water with your dog. as you look westward into the ocean, you throw a tennis ball out into the water. the ball lands in the water 20 meters north and 13 meters west of where you are standing. the dog swims at 5 m/s but runs at 13 m/s. how far north does the dog run before jumping in the water to minimize his time to get to the ball? assume the coastline is straight and ignore both water currents and wind drag.