A wheel of radius 0.2 m rotates freely about its center when a string that is wrapped over its rim is pulled by force of 10 N as shown in figure. The established torque produces an angular acceleration of $2 \mathrm{rad} / \mathrm{s}^{2}$. Moment of intertia of the wheel is $\_\_\_\_$ $\mathrm{kgm}^{2}$. (Acceleration due to gravity $=10 \mathrm{~m} / \mathrm{s}^{2}$ )