[tex]dane:\\F = 2 \ 000 \ N\\s = 2 \ km = 2 \ 000 \ m\\t = 30 \ min = 30\cdot60 \ s = 1 \ 800 \ s\\szukane:\\P = ?\\\\P = \frac{W}{t}\\\\W = F\cdot s = 2 \ 000 \ N \cdot2 \ 000 \ m = 4 \ 000 \ 000 \ J\\\\P = \frac{4 \ 000 \ 000 \ J}{1 \ 800 \ s} \approx 2 \ 222 \ W[/tex]
