A communications satellite is moving at a constant speed in a circular orbit around Earth. At any given instant in time, what is the resultant force on the satellite?
A. zero
B. equal to the gravitational force on the satellite
C. equal to the vector sum of the gravitational force on the satellite and the centripetal force
D. equal to the force exerted by the satellite's rockets
To determine the resultant force on a communications satellite moving at a constant speed in a circular orbit around Earth, we need to understand the forces acting on the satellite.
1. Gravitational force: The satellite experiences a gravitational force directed towards the center of the Earth. This force keeps the satellite in orbit.
2. Centripetal force: In order for the satellite to move in a circular path, it requires a centripetal force directed towards the center of the orbit. This force is provided by the gravitational force.
Based on these forces, we can evaluate the different options:
A. Resultant force of zero: This is incorrect because both the gravitational force and the centripetal force are acting on the satellite, and they are not equal and opposite forces.
B. Resultant force equal to the gravitational force: This is incorrect because the satellite is in a circular orbit, which means it is constantly accelerating towards the center of the circle. Therefore, the gravitational force alone cannot be the resultant force.
C. Resultant force equal to the vector sum of the gravitational force and the centripetal force: This is the correct answer. The gravitational force and the centripetal force are both acting on the satellite. The resultant force can be found by adding these two vectors together.
D. Force exerted by the satellite's rockets: This is incorrect because in this scenario, we assume the satellite is moving at a constant speed and does not require additional force from rockets.
So, the correct answer is C. The resultant force on the satellite is equal to the vector sum of the gravitational force and the centripetal force.
The resultant force on the communication satellite moving at a constant speed in a circular orbit around Earth is:
C. equal to the vector sum of the gravitational force on the satellite and the centripetal force.
Explanation:
In a circular orbit, the satellite experiences two forces: the gravitational force pulling it towards the center of the Earth and the centripetal force pulling it towards the center of the circular path. These two forces are acting in different directions. The centripetal force is necessary to keep the satellite moving in a circular path, while the gravitational force provides the necessary acceleration towards the center of the earth.
Since the satellite is moving at a constant speed, the net force on the satellite must be zero. This means that the gravitational force and the centripetal force must balance each other out. Thus, the resultant force on the satellite is equal to the vector sum of the gravitational force and the centripetal force.