A parabolic pulse given by equation $y\left(\mathrm{in} \mathrm{cm}\right)=0.3-0.1{\left(x-5t\right)}^2\left(y\ge 0\right)$ travelling in a uniform string. The pulse passes through a boundary beyond which its velocity becomes $2.5 \mathrm{m} {\mathrm{s}}^{-1}$. What will be the amplitude (in $\mathrm{cm}$) of pulse in this medium after transmission?