${?}^{**}.$ The Geneva mechanism is used in a packaging system to convert constant angular motion into intermittent angular motion. The star wheel A makes one sixth of a revolution for each full revolution of the driving wheel $B$ and the attached guide $C.$ To do this, pin $P,$ which is attached to $B,$ slides into one of the radial slots of $A,$ thereby turning wheel $A,$ and then exits the slot. If $B$ has a constant angular velocity of ${}_B=4ra\frac{d}{s},$ determine ${}_A$ and ${}_A$ of wheel $A$ at the instant shown.