1. The problem statement, all variables and given/known data A solid sphere, starting from rest, rotates with constant angular acceleration α about a fixed axis passing through its center. Consider a particle within this sphere that lies at a perpendicular distance r from this axis. If, at some instant, the linear acceleration of this particle makes an angle of 50° with respect to the direction of its tangential acceleration, what is the total angle that the sphere has turned through up until that instant? 2. Relevant equations tangential acceleration = αr centripetal acceleration = ω^2r 3. The attempt at a solution Since the angular acceleration is constant, the tangential acceleration would also remain constant and I don't see how the angle could be changing.