Odpowiedź :
[tex]dane:\\m = 4 \ kg\\v = 18\frac{km}{h} = 18\cdot\frac{1000 \ m}{3600 \ s} = 5\frac{m}{s}\\szukane:\\E_{k} = ?\\\\E_{k} = \frac{1}{2}mv^{2}\\\\E_{k} = \frac{1}{2}\cdot4 \ kg\cdot(5\frac{m}{s})^{2}\\\\E_{k} = 50 \ J[/tex]
[tex]dane:\\m = 4 \ kg\\v = 18\frac{km}{h} = 18\cdot\frac{1000 \ m}{3600 \ s} = 5\frac{m}{s}\\szukane:\\E_{k} = ?\\\\E_{k} = \frac{1}{2}mv^{2}\\\\E_{k} = \frac{1}{2}\cdot4 \ kg\cdot(5\frac{m}{s})^{2}\\\\E_{k} = 50 \ J[/tex]