Kinematics - Intrinsic components of the acceleration and radius of curvature OK

A point moves on a curve ¿¿^2=4 following the time law ¿ =4¿ (meters and second). Find for ¿=1 s: a) the velocity vector and its magnitude; b) the acceleration vector; c) the intrinsic components of the acceleration. d)The radius of curvature.