\[ \left\{\begin{array}{cccc} N_{av}=1400\,\rm{rpm} \\ \Delta E_{max}=1150\,\rm{kg\cdot cm} \times 9.81\,\rm{m/s^2} \\ \delta_f=0.01 \\ \kappa =0.15\,\rm{m} \end{array}\right. \] \[ \begin{align} J &=\frac{1150 \times 10^{-2}\,\rm{kg \cdot m} \times 9.81 \,\rm{m/s^2}}{0.01 \times \left(\frac{2\pi \times 1400\,\rm{rpm}}{60}\right)^2} \\ &=0.5248\,\rm{kg\cdot m^2} \end{align} \] \[ J=m\cdot \kappa^2\ より \\ \\ \begin{align} m &=\frac{J}{\kappa ^2} \\ &=\frac{0.5248\,\rm{kg\cdot m^2}}{(0.15\,\rm{m})^2} \\ &=23.32\,\rm{kg} \end{align} \] \[ \therefore m=23.3 \ \,\rm{kg} \]