Two $100-mm$ rods A and $B,$ each of mass $300$ g $,$ are welded to the shaft $CD$ which is supported by bearings at $C$ and $D.$ If a couple M of moment equal to $6N*m$ is applied to the shaft, determine the components of the dynamic reactions at $D$ at the instant when the shaft has reached an angular velocity of $1200$ rpm$.$ Neglect the moment of inertia of the shaft itself.

A$.D_z=-38\mathrm{.}1N,D-y=-131\mathrm{.}9N$

B$.D_{-}z=-36\mathrm{.}8N,D_{-}y=-129\mathrm{.}8N$

C$.D_{-}z=-40\mathrm{.}4N,D-y=-136\mathrm{.}7N$

D$.D_{-}z=-43\mathrm{.}7N,D_{-}y=-138\mathrm{.}5N$