= 1,2 , h = 20 ., ρ= 13600 /3.
5. 9 ., , . 1 = 3*105 t1=-23C?, . t2=77
-05
l = 50 N = 300, , , S = 5 2. R = 0.02 . .
-
1. f
: .
12-14 1997
- JBT-1325W ()
6-
PIC
5-
.