Is an object moving in a circle at a constant speed accelerating?

yes.

Accelerating objects are objects which are changing their velocity - either the speed (i.e., magnitude of the velocity vector) or the direction. An object undergoing uniform circular motion is moving with a constant speed.

Explanation:

it is true because as we rotate around the way we rotate makes day come and because the moon is rotating around the earth that's what makes it night come. hope this .