How is satellite in orbit maintained?

In space gravity supplies the centripetal force that causes satellites to orbit larger bodies. if you know the mass and altitude of a satellite in orbit around the Earth, you can calculate how quickly it needs to travel to maintain that orbit.

Nps pollution is caused by rainfall or snowmelt moving over and through the ground. nonpoint source pollution can include: excess fertilizers, herbicides and insecticides from agricultural lands and residential areas. oil, grease and toxic chemicals from urban runoff and energy production