1.
[tex]Dane:\\s = 1 \ km = 1000 \ m\\W = 36 \ kJ = 36 \ 000 \ J\\Szukane:\\F = ?\\\\Rozwiazanie\\\\W = F\cdot s \ \ /:s\\\\F = \frac{W}{s}\\\\F = \frac{36000 \ J}{1000 \ m} = \frac{36000 \ N\cdot m}{1000 \ m}\\\\\boxed{F = 36 \ N}[/tex]
Odp. Szukana siła ma wartość 36 N (niutonów).
2.
[tex]Dane:\\m = 100 \ kg\\E_{k} = 5 \ kJ = 5 \ 000 \ J\\Szukane:\\v = ?\\\\Rozwiazanie\\\\E_{k} = \frac{mv^{2}}{2} \ \ |\cdot2\\\\mv^{2} = 2E_{k} \ \ /:m\\\\v^{2} = \frac{2E_{k}}{m} \ \ |\sqrt{}\\\\v = \sqrt{\frac{2E_{k}}{m}}\\\\v = \sqrt{\frac{2\cdot5000 \ J}{100 \ kg}}} = \sqrt{\frac{10000 \ kg\cdot\frac{m^{2}}{s^{2}}}{100 \ kg}}}}=\sqrt{100\frac{m^{2}}{s^{2}}}\\\\\boxed{v = 10\frac{m}{s}}[/tex]
Odp. To ciało porusza saię z prędkością v = 10 m/s.
