A $2\mathrm{.}92-$m$-$diameter merry$-$go$-$round is rotating freely with an angular velocity of $0\mathrm{.}82$ rad$/$s$.$ Its total moment of inertia is $1,551$ kg$$m$2.$ Four people standing on the ground, each of mass $86$ kg$,$ suddenly step onto the edge of the merry$-$go$-$round. What is the angular velocity $($in rad$/$s$)$ of the merry$-$go$-$round now? Write down the answer up to two decimal points.