On the right is the view from the rotating frame. The particle has velocity
Urot in the rotating frame. The relation between u in and u rot is
uin=urot+Ω×r where Ω × r is the velocity of a particle fixed (not moving) in the rotating frame at position vector r. The relationship between the rate of change of any vector A in the rotating frame and the change of A as seen in the inertial frame is given by rotating frame are not fixed, but are rotating at rate Ω and so