1. The problem statement, all variables and given/known data Acceleration is a vector representing the rate of change of velocity. An object moving in a circle at constant speed: A. accelerates without changing its velocity B. Has constant acceleration C. Changes speed but not velocity D. Changes velocity but not speed 2. Relevant equations Arad=V2/R 3. The attempt at a solution The answer given in my book is D, which makes sense, but I also don't see how B is wrong. If the object's speed is constant, and radial acceleration is based off the magnitude of velocity (hence changing direction of velocity doesn't affect it), then shouldn't the acceleration also be constant?