Problem $2.(6$ points$)$

The $100-$g block $B$ shown in the figure slides along

the rotating bar $OA.$ The coefficient of kinetic

friction between $B$ and $OA$ is ${}_k=0\mathrm{.}2.$

In the position shown, $R^{}=1\frac{m}{s},{}^{}=5ra\frac{d}{s},$ and

${}^{}=3ra\frac{d}{s^2}.$ For this position,

A$)$ Draw the free body diagram and the kinetic

diagram

B$)$ Use the equations of motion to determine $R^{}.$