Question

which best explains why a satellite accelerates?
it is always changing direction.
it is constantly slowed by gravity.
it does not have forces acting on it.
it is weightless when it is in orbit.

Explanation:

Acceleration is a change in velocity. Velocity is a vector (has magnitude and direction). A satellite in orbit is constantly changing direction (even if speed magnitude is constant). By definition of acceleration (change in velocity), this means it is accelerating. Gravity is a force acting on the satellite (so options about no forces or being slowed by gravity in a non - acceleration - related way are wrong). Weight is related to the force of gravity, and the satellite is not weightless (it has gravitational force acting on it, just in free - fall).

Answer:

It is always changing direction.