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.

Answer 1

"It is always changing direction."

Acceleration is any change in velocity (magnitude or direction). A satellite in orbit moves at (nearly) constant speed but continuously changes direction, so it undergoes centripetal acceleration toward Earth caused by gravity.