[tex]dane:\\v = 36\frac{km}{h} = 10\frac{m}{s}\\W = 40 \ J\\szukane:\\m = ?\\\\Rozwiazanie\\\\W = E_{k} = \frac{mv^{2}}{2}\\\\W = \frac{mv^{2}}{2} \ \ /\cdot 2\\\\mv^{2} = 2W \ \ /:v^{2}\\\\m = \frac{2W}{v^{2}}\\\\m = \frac{2\cdot40 \ J}{(10\frac{m}{s})^{2}} = \frac{80 \ kg\cdot\frac{m^{2}}{s^{2}}}{100\frac{m^{2}}{s^{2}}} = 0,8 \ kg[/tex]
Odp. Masa ciała wynosi 0,8 kg.
