Centripetal Force in Orbital Motion

Steps:

• Satellite orbits at steady speed, indicating uniform circular motion around the planet.
• Constant speed means velocity direction changes continuously, requiring centripetal acceleration toward the orbit's center.
• Resultant force causes this acceleration, directed radially inward per Newton's second law (F = ma).
• Gravity from the planet provides this force, pointing toward the planet's center.

Why A is correct:

• A points toward the planet, matching the direction of gravitational force that supplies centripetal force for circular orbit (F_c = GMm/r²).

Why the others are wrong:

• B (tangential): Would accelerate speed, but speed remains steady.
• C (outward): Opposes gravity, causing satellite to escape orbit.
• D (perpendicular to radius): Does not provide required inward acceleration for circular path.

Final answer: A