2}}}}}{{{U}_{He}}}=\frac{1}{2}=\sqrt{\frac{{{M}_{He}}}{{{M}_{S{{O}_{2}}}}}\frac{{{T}_{S{{O}_{2}}}}}{{{T}_{He}}}}=\sqrt{\frac{4}{64}.\frac{{{T}_{S{{O}_{2}}}}}{300}}\] \[=\frac{4}{64}\frac{{{T}_{S{{O}_{2}}}}}{300}=\frac{1}{4}\]; \[{{T}_{S{{O}_{2}}}}={{1200}^{o}}K\]