1/d+1/f=1/F
d=f
1/d+1/d=1/F
2/d=1/F
F=d/2=12,5 см
V=252км/ч=70м/с. V0=0. S=980м. S=(V0+V)*t/2. t=2S/V. t=2*980/70=28 c
V2 : v1 = t2 : t1 ; t2 = t1 * (v2:v1) ; v2 = v1 : 2 ; t2 = t1:2
t1 = 819 + 273 = 1092 k
t2 = 1092 : 2 = 546 k
t2 = 546 - 273 = 273 (C-цельсий)
<span>Подробно 1. R=120, I=220/120=1.833, P=1.833*220=403.33 2. R=120+120=240, I=220/240=0.916, P=0.916*220=201.66 3. 1/R=1/120+1/120, R=60, I=220/60=3.666, P=3.666*220=806.66</span>