Correct Response: C. The weight of the space station and the gravitational force of the space station on Earth is the only answer choice that represents an action-reaction pair. The weight of the space station is the force of Earth's gravity on the space station. This force is equal in magnitude and opposite in direction to the gravitational force of the space station on Earth. The weight of the space station and the centripetal force on the space station (A) are not an action-reaction pair. The weight of the space station is the force of Earth's gravity on the space station. This is the same as the centripetal force on the space station, which is also the force of Earth's gravity on the space station. The weight of the astronauts and the centripetal force on the space station (B) are not an action-reaction pair. The weight of the astronauts is the force of Earth's gravity on the astronauts. Its action-reaction pair is the gravitational force of the astronauts on Earth. It is not the centripetal force on the space station, which equals the force of Earth's gravity on the space station. The weight of the astronauts and the gravitational force of the space station on the astronauts (D) are not an action-reaction pair. The weight of the astronauts is the force of Earth's gravity on the astronauts. This is independent of the gravitational force of the space station on the astronauts.
