A solid disc of radius $r$ rolls without slipping on a horizontal floor with angular velocity $\omega$ and angular acceleration $\alpha$. The magnitude of the acceleration of the point of contact on the disc is

(A) zero

(B) $r \alpha$

(C) $\sqrt{(r \alpha)^{2}+\left(r \omega^{2}\right)^{2}}$

(D) $r \omega^{2}$

A solid disc of radius $r$ rolls without slipping on a horizontal floor with angular velocity $\omega$ and angular acceleration $\alpha$. The magnitude of the acceleration of the point of contact on the disc is

(A) zero

(B) $r \alpha$

(C) $\sqrt{(r \alpha)^{2}+\left(r \omega^{2}\right)^{2}}$

(D) $r \omega^{2}$

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