if a satellite moves in a circular orbit around a planet, the satellite has a constant:
momentum
velocity OR
acceleration
velocity
In a circular orbit around a planet, the satellite has a constant velocity.
To understand why this is the case, we can consider the concept of centripetal force. In a circular orbit, the gravitational force between the planet and the satellite provides the necessary centripetal force to keep the satellite in its orbit.
Centripetal force is defined as the force that acts towards the center of the circular path. In the case of satellite motion, the gravitational force between the planet and the satellite provides this inward force.
According to Newton's second law of motion, the net force acting on an object is equal to the product of its mass and acceleration (F = m * a). In the case of circular motion, the inward centripetal force is balanced by the outward centrifugal force.
Therefore, the satellite experiences a continuous change in direction due to the centripetal force acting on it, but its speed remains constant, resulting in a constant velocity. This means the satellite maintains a consistent orbital speed throughout its circular path around the planet.
So, to answer your question, if a satellite moves in a circular orbit around a planet, the satellite has a constant velocity.
This is a very poorly worded question.
All three are constant in magnitude but vary in direction.
Since that are all vectors (with both magnitude and direction), none are constant.