The $3\mathrm{.}6-$lblb rod ABAB is hanging in the vertical position. A $1\mathrm{.}6-$lblb block, sliding on a smooth horizontal surface with a velocity of $12$ ft$/$sft$/$s$,$ strikes the rod at its end BB$.$

$($Figure $1)$

Figure

$1$ of $1$

Part A

Determine the velocity of the block immediately after the collision. The coefficient of restitution between the block and the rod at BB is ee $=0\mathrm{.}79.$

Express your answer to three significant figures and include the appropriate units.