Odpowiedź :
[tex]dane:\\P = 80 \ W\\t = 45 \ min = 45\cdot60 \ s = 2700 \ s\\szukane:\\W = ?\\\\P = \frac{W}{t} \ \ /\cdot t\\\\W = P\cdot t\\\\W = 80 \ W\cdot2700 \ s\\\\W = 216 \ 000 \ J = 216 \ kJ[/tex]
[tex]dane:\\P = 80 \ W\\t = 45 \ min = 45\cdot60 \ s = 2700 \ s\\szukane:\\W = ?\\\\P = \frac{W}{t} \ \ /\cdot t\\\\W = P\cdot t\\\\W = 80 \ W\cdot2700 \ s\\\\W = 216 \ 000 \ J = 216 \ kJ[/tex]