A merry$-$go$-$round is a common piece of playground equipment. A $3\mathrm{.}0-$m$-$diameter merry$-$go$-$round, which can be modeled as a disk with a mass of $260$ kg $,$ is spinning at $17$ rpm $.$ John runs tangent to the merry$-$go$-$round at $\backslash (5\mathrm{.}8\backslash$mathrm$\{$~m$\}/\backslash$mathrm$\{$s$\}\backslash ),$ in the same direction that it is turning, and jumps onto the outer edge. John's mass is $30$ kg $.$