[tex]Ek=\frac{mv^{2} }{2} |*2\\\\\2Ek=mv^{2} |:m\\\\\frac{2Ek}{m} =v^{2} |\sqrt{} \\\\\sqrt{\frac{2Ek}{m} } =v\\\v=\sqrt{\frac{2Ek}{m} }[/tex]
