The linear density of a vibrating string is $1.3\times 10^{-4}\mathrm{ }\mathrm{k}\mathrm{g} {\mathrm{m}}^{-1}$ . A transverse wave is propagating on the string and its described by the equation $\mathrm{y}=0.021\sin \left(\mathrm{x}+30\mathrm{t}\right)$ , where $\mathrm{x}$ and $\mathrm{y}$ are measured in $\mathrm{m}$ and $\mathrm{t}$ in $\mathrm{s}$ . The tension in the string is