Kinetic energy possessed by moving train is [tex]E_k = 150000J[/tex].
And mass [tex]m = 10000kg[/tex].
The formula for kinetic energy is [tex]E_k = \frac{m\times v^2}{2}[/tex].
Solve for velocity:
[tex]E_k = \frac{m\times v^2}{2}\implies 2E_k = m\times v^2[/tex]
[tex]v^2=\frac{2E_k}{m}\implies \underline{v = \sqrt{\frac{2E_k}{m}}}[/tex]
Now put in the data:
[tex]v = \sqrt{\frac{2\times150000J}{10000kg}}\approx5.48\frac{m}{s}[/tex]
