A fly wheel having mass 3 kg and radius 5 m is free to rotate about a horizontal axis. A string having negligible mass is wound around the wheel and…

A fly wheel having mass $\displaystyle 3$ kg and radius $\displaystyle 5$ m is free to rotate about a horizontal axis. A string having negligible mass is wound around the wheel and the loose end of the string is connected to $\displaystyle 3$ kg mass. The mass is kept at rest initially and released. Kinetic energy of the wheel when the mass descends by $\displaystyle 3$ m is $\displaystyle \_\_\_\_$J. $\displaystyle \left(\mathrm{g}=10 \mathrm{~m} / \mathrm{s}^2\right)$