Where does the name "black hole" get it's name?

The earth exerts a gravitational force of 500 n on amy. what is amy’s mass in kg?

Asatellite with an orbital period of exactly 24.0 h is always positioned over the same spot on earth. this is known as a geosynchronous orbit. television, communication, and weather satellites use geosynchronous orbits. at what distance would a satellite have to orbit earth in order to have a geosynchronous orbit?

Element with 3protons and 5neutrons