[tex]2)\\dane:\\m = 0,3 \ kg\\E_{k} = 9 \ 000 \ J\\szukane:\\v = ?\\\\E_{k} = \frac{mv^{2}}{2} \ \ /\cdot\frac{2}{m}\\\\v^{2} = \frac{2E_{k}}{m}\\\\v = \sqrt{\frac{2E_{k}}{m}}}\\\\v = \sqrt{\frac{2\cdot9000 \ J}{0,3 \ kg}} = \sqrt{\frac{18000 \ kg\cdot\frac{m^{2}}{s^{2}}}{0,3 \ kg}} = \sqrt{60000\frac{m^{2}}{s^{2}}}}\\\\v \approx244,95\frac{m}{s}[/tex]
