Odpowiedź:
1.) 39200N = 39,2 kN , 2.) 22,22W
Wyjaśnienie:
Zad.1
P = 980 kW = 980 000 W ( moc)
V = 90 km/h = 90 * [tex]\frac{1000m}{3600s}[/tex] = 25 [tex]\frac{m}{s}[/tex] ( prędkość)
F = ? (siła)
W ( praca)
t (czas)
[tex]P= \frac{W\\}{t}[/tex]
[tex]P = \frac{F*S}{t}[/tex]
P = F*V /:V
[tex]F = \frac{P}{V}[/tex] = [tex]\frac{980000W}{25\frac{m}{s} }[/tex] = 39200 N
Zad.2
F = 0,04 kN = 40N
t= 72 min = 4320 s
S = 2,4 km = 2400m
[tex]P= \frac{W\\}{t}[/tex]
[tex]P = \frac{F*S}{t}[/tex]
P = [tex]\frac{40N *2400m}{4320s}[/tex] = [tex]\frac{96000 J}{4320s} =22,22 W[/tex]
