Page 523 - index

Q ˜ dz dM , dM Q. (7.2)
dz

ɋɨɧɵɦɟɧ, ɤԧɥɞɟɧɟԙ ɤԛɲ (Q), ɢɸɲɿ ɦɨɦɟɧɬɬɿԙ ɛɿɪɿɧɲɿ ɬɭɵɧɞɵɫɵ ɟɤɟɧɿɧɟ
ɤԧɡɿɦɿɡ ɠɟɬɟɞɿ. ɋɨԙԑɵ ɬɟԙɞɿɤɬɿԙ ɟɤɿ ɠɚԑɵɧ ɞɚ z ɛɨɣɵɧɲɚ ɞɢɮɮɟɪɟɧɰɢɚɥɞɚɩ,
ɨɧɵ (7.1) ɬɟԙɞɿɤɤɟ ԕɨɹɦɵɡ:

d 2M q. (7.3)
dz 2

Ȼԝɥ ɬɟԙɞɿɤ ɢɸ ɦɨɦɟɧɬɿɧɿԙ ɟɤɿɧɲɿ ɬɭɵɧɞɵɫɵ – ɬɚɪɚɥԑɚɧ ɤԛɲɬɿԙ
ԕɚɪԕɵɧɞɵɥɵԑɵ ɟɤɟɧɿɧ ɤԧɪɫɟɬɟɞɿ. Ɉɫɵ ɚɥɵɧԑɚɧ ԛɲ ɞɢɮɮɟɪɟɧɰɢɚɥɞɵԕ
ɬԥɭɟɥɞɿɥɿɤɬɟɪɞɿ ɩɚɣɞɚɥɚɧɚ ɨɬɵɪɵɩ, ɢɸɲɿ ɦɨɦɟɧɬ ɩɟɧ ɤԧɥɞɟɧɟԙ ɤԛɲɬɿԙ
ɷɩɸɪɚɥɚɪɵɧɵԙ ɞԝɪɵɫɬɵԑɵɧ ɬɟɤɫɟɪɭɝɟ ɛɨɥɚɞɵ.

§ 3. Ɍɚɡɚ ɢɿɥɭɞɟɝɿ ɤɟɪɧɟɭ
ɀɨԑɚɪɵɞɚ ɚɣɬɵɥԑɚɧɞɚɣ, ɬɚɡɚ ɢɿɥɭ ɤɟɡɿɧɞɟ ɚɪԕɚɥɵԕɬɵԙ ԕɢɦɚɫɵɧɞɚ
ɤԧɥɞɟɧɟԙ ɤԛɲ ɛɨɥɦɚɣɞɵ, ɹԑɧɢ Q=0. Ɉɫɵɧɞɚɣ ɬɚɡɚ ɢɿɥɿɩ ɬԝɪԑɚɧ ɚɪԕɚɥɵԕɬɵ
ɚɥɵɩ ԕɚɪɚɣɵԕ (85-ɫɭɪɟɬ). Ȼԝɥ ɚɪԕɚɥɵԕɬɵ, ɨԙ ɠɚԕ ɲɟɬɤɿ ԕɢɦɚɞɚɧ z
ԕɚɲɵԕɬɵԕɬɚ ɤɟɫɟɣɿɤ. ɋɨɥ ɠɚԕɬɚԑɵ ɛԧɥɿɤɬɿ ɚɥɵɩ ɬɚɫɬɚɩ, ԕɚɥԑɚɧ ɛԧɥɿɤɬɿԙ (86-
ɫɭɪɟɬ) ɫɬɚɬɢɤɚɥɵԕ ɬɟԙɞɿɝɿɧ ԕɚɪɚɫɬɵɪɚɦɵɡ.

Ɉɫɵ ɨԕɭɥɵԕɬɵԙ 6-ɬɚɪɚɭɵɧɚɧ ɛɟɥɝɿɥɿ ɫɬɚɬɢɤɚɧɵԙ ɚɥɬɵ ɬɟԙɞɟɭɿɧ ԕԝɪɚɣɵԕ:
1) 6x 0 ;

2) 6y 0 ,

dN ɤԛɲɿ ɞɟ, ɢɸɲɿ ɦɨɦɟɧɬ ɬɟ (Ɇ) ɛԝɥ ɨɫɶɬɟɪɝɟ ɩɪɨɟɤɰɢɹɥɚɧɛɚɣɞɵ,
ɫɨɧɞɵԕɬɚɧ 0=0;

3) 6z 0. Ÿ dN 0 Ÿ dN V ˜ dȺ ɛɨɥԑɚɧɞɵԕɬɚɧ

N ³V ˜ dȺ . (7.4)
A

85-ɫɭɪɟɬ
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