$4\mathrm{.}91$ Two tape spools are attached to an axle supported by bearings at

A and $D.$ The radius of spool $B$ is $30$ mm and the radius of spool $C$ is $40$ mm $.$

Knowing that $T_B=80N$ and that the system rotates at a constant rate, deter$-$

mine the reactions at A and $D.$ Asstume that the bearing at A does not exert

any axial thrust and neglect the weights of the spools and axle.

Fig. P$4\mathrm{.}91$

$4\mathrm{.}92$ Solve Prob. $4\mathrm{.}91,$ assuming that the spool $C$ is replaced by a spool

of radius $50$ mm $.$