Forgive my rusty English. But I really need urgent and Professional help, teachers and professors, please: A satellite has been put on Earth's orbit at a high speed, (forget atmosphere friction, forget moon attraction, forget sun gravity), theoretically, without any further thrust, will it stay on Earth's orbit forever? Many people in my country told me it will, but I doubt it, because Earth's gravity pull is continuous (in acceleration = a), and the satellite needs force to balance out the gravitational pull (F=m a) as centripedal/centrifugal force, then the gravity's <a> has been cancelled in the equation F=m<a>, since mass is constant, then that means WE NEED <CONSTANT> FORCE to balance out the gravity pull, that means the satellite needs CONSTANT Force to stay on orbit. Am I correct? Thanks.