george walks to a friend's house. he
walks 750 meters north, then realizes
he walked too far. he turns around
and walks 250 meters south. the
entire walk takes him 13 seconds.
what is his speed per second?

While standing outdoors one evening, you are exposed to the following four types of electromagnetic radiation: yellow light from a sodium street lamp, radio waves from an am radio station, radio waves from an fm radio station, and microwaves from an antenna of a communications system. rank these type of waves in terms of increasing photon energy.