Step 1: Understanding centripetal force.
The centripetal force \( F_c \) on a particle moving in a circle of radius \( r \) with velocity \( v \) is given by:
\[
F_c = \frac{mv^2}{r}
\]
Since \( v = r\omega \), where \( \omega \) is the angular velocity, the expression for centripetal force becomes:
\[
F_c = m \omega v
\]
Step 2: Conclusion.
Thus, the magnitude of the centripetal force is \( m \omega v \), corresponding to option (D).