A solid sphere rolls purely on a level horizontal surface. The linear velocity of the centre is $v$.

STATEMENT-1: The radius of curvature of a particle at point $A$ in the ground frame and the frame attached with the centre of sphere $O$ is numerically the same.

STATEMENT-2: The frame attached with $O$ is moving with a constant velocity w.r.t. the ground frame and hence is inertial (considering ground frame as inertial frame).