Hello
The kinetic energy K of a moving object is:
[tex]K= \frac{1}{2} m v^2 [/tex]
where m is the mass and v the velocity of the object.
Using this formula, we can calculate v for this problem:
[tex]v= \sqrt{ \frac{2E}{m} }= \sqrt{ \frac{2\cdot30400~J}{950~Kg} } = 8~m/s [/tex]