[tex]dane:\\h = 20 \ m\\m = 2,4 \ t = 2 \ 400 \ kg\\t = 2 \ min = 2\cdot60 \ s = 120 \ s\\szukane:\\g = 10\frac{N}{kg}\\P = ?\\\\Rozwiazanie\\\\P = \frac{W}{t}\\\\W = E_{p} = mgh\\\\P = \frac{mgh}{t}\\\\P = \frac{2400 \ kg\cdot10\frac{N}{kg}\cdot20 \ m}{120 \ s} = \frac{480000 \ J}{120 \ s} = 4 \ 000 \ W = 4 \ kW[/tex]
