A satellite is in a circular orbit around Earth at an altitude where the gravitational field strength is 4.5 m/s². What is the centripetal acceleration of the satellite?

Core Concept

For a satellite in circular orbit, the only force acting on it is gravity, which provides the centripetal force needed for circular motion. According to Newton's second law, F = ma, where F is the gravitational force and a is the centripetal acceleration. The gravitational field strength (g) is defined as the gravitational force per unit mass, so g = F/m. Therefore, the centripetal acceleration must equal the gravitational field strength at that point, which is 4.5 m/s². Option A is incorrect because the satellite is accelerating (changing direction). Option C is the surface gravity of Earth, not at the satellite's altitude. Option D is the sum of the satellite's gravitational field and Earth's surface gravity, which has no physical meaning in this context.