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.

The dipole moment of the water molecule (h2o) is 6.17x10^-30 c. m. consider a water molecule located at the origin whose dipole moment p points in the +x-direction. a chlorine ion ( of charge-1.60x10^-19c , is located at x=3.00x10^-9m . assume that is much larger than the separation d between the charges in the dipole, so that the approximate expression for the electric field along the dipole axis can be used. a) find the magnitude of the electric force that the water molecule exerts on the chlorine ion. b) what is the direction of the electric force. -x-direction or +x-direction c) is this force attractive or repulsive?