Each of the four corners of a square with edge 3.0 m is occupied by a point mass 12 kg. There is a fifth mass, also 12 kg, at the center of the square. To remove the mass from the center to a point far away, how much work that must be done by an external agent

Sally turns on her cellular telephone to speak to her friend who is located thousands of miles away. which of the following best describes how such a telephone is able to transmit and receive information? a. the cellular telephone transmits, receives, and encodes information using only sound waves. b. the cellular telephone transmits, receives, and encodes information using only electromagnetic waves. c. the cellular telephone transmits information by electromagnetic waves to a receiver which then encodes them and produces sound. d. the cellular telephone transmits information by sound waves to a receiver which then encodes them and produces electromagnetic waves.