$5/122$ The $9-$ft steel beam is being hoisted from its hori$-$

zontal position by the two cables attached at $A$

and $B.$ If the initial angular accelerations are

${}_1=0\mathrm{.}2ra\frac{d}{se{c}^2}$ and ${}_2=0\mathrm{.}6ra\frac{d}{se{c}^2},$ determine

the initial values of $(a)$ the angular acceleration

of the beam, $(b)$ the acceleration of point $C,$ and $($c$)$

the distance $d$ from $A$ to the point on the center$-$

line of the beam which has zero acceleration.

Problem $5/122$