Question

Which statements accurately describe satellite motion? Check all that apply.

Gravity is the only force acting on a satellite.
Inertia is the only cause of a satellite’s circular motion.
Air resistance prevents satellites from staying in orbit for very long.
Circular orbits result from the interaction between gravity and inertia.
Gravity provides the centripetal force for satellites.
Satellites are in free fall around Earth or other central objects

Answer 1

Correct choices:
- Circular orbits result from the interaction between gravity and inertia. (True — the satellite’s tangential motion (inertia) together with gravity producing a centripetal pull yields a curved (circular) path.)
- Gravity provides the centripetal force for satellites. (True — the gravitational attraction toward the central body supplies the inward force that keeps the satellite in orbit.)
- Satellites are in free fall around Earth or other central objects. (True — an orbiting satellite is continuously falling toward the central body but has enough tangential speed to keep missing it.)

Why the others are not generally correct:
- "Gravity is the only force acting on a satellite." — Not always true; non‑gravitational forces (atmospheric drag, solar radiation pressure, thrust maneuvers, magnetic forces, etc.) can act.
- "Inertia is the only cause of a satellite’s circular motion." — Inertia alone would produce straight-line motion; circular motion requires both inertia (tangential velocity) and gravity (centripetal force).
- "Air resistance prevents satellites from staying in orbit for very long." — Air drag affects low-Earth satellites and causes orbital decay, but satellites at higher altitudes experience negligible air resistance and can remain for decades or longer.