Final answer:
The speed of a satellite circling the Earth is determined by gravitational forces and the distance from Earth's center, with the mass of the satellite and atmospheric conditions being less significant factors in most situations.
Step-by-step explanation:
The speed of a satellite circling the Earth is primarily determined by the gravitational pull exerted by the Earth on the satellite and the distance of the satellite from the center of the Earth, rather than the mass of the satellite or atmospheric conditions, especially when considering orbits outside the Earth's atmosphere where air resistance is negligible.
Following Newton's law of universal gravitation and his second law of motion, we can deduce that for a satellite in a circular orbit, the gravitational force provides the necessary centripetal force to keep the satellite in orbit. The orbital velocity of a satellite in a circular orbit can be computed using the formula v = √(GM/r), where G is the gravitational constant, M is the mass of the Earth, and r is the radius of the orbit.
The speed of the satellite will decrease as the distance from the Earth increases. This is because, as the satellite moves into larger orbits, it has higher potential energy and requires less velocity to sustain its orbit. Moreover, to remain in geostationary orbit, a satellite must satisfy several conditions, including a 24-hour orbital period, an equatorial orbit, and synchronization with Earth's rotation.