Page 540 - index

ɢɧɞɟɤɫ – ɤɟɪɧɟɭ ɠɚɬԕɚɧ ɠɚɡɵԕɬɵԕԕɚ ɧɨɪɦɚɥɶ ɨɫɶɬɿԙ ɛɟɥɝɿɫɿ (W xy ,W yz ,W zx ).

Ʉɟɥɬɿɪɿɥɝɟɧ 100-ɫɭɪɟɬɬɟ ɩɚɪɚɥɥɟɥɟɩɢɩɟɞɬɿԙ ԧɡɚɪɚ ɩɟɪɩɟɧɞɢɤɭɥɹɪ ԛɲ
ɠɚԑɵɧɞɚɵ ɤɟɪɧɟɭɥɟɪ ɤԧɪɫɟɬɿɥɝɟɧ, ɚɥ ɨɧɵԙ ɤԧɪɿɧɛɟɣɬɿɧ ԕɚɥԑɚɧ ԛɲ ɠɚԑɵɧɞɚ
ɨɫɵɧɞɚɣ ɤɟɪɧɟɭɥɟɪ ɛɚɪ, ɨɥɚɪ ԕɚɪɚɦɚ-ԕɚɪɫɵ ɠɚԕԕɚ ɛɚԑɵɬɬɚɥԑɚɧ ɠԥɧɟ
ɲɚɦɚɥɚɪɵɧɵԙ ԕɚɪɫɵ ɛɟɬɬɟɝɿɥɟɪɦɟɧ ɫɚɥɵɫɬɵɪԑɚɧɞɚ, ɨɥɚɪɞɚɧ ɷɥɟɦɟɧɬɚɪ
ɚɣɵɪɦɚɲɵɥɵԕɬɚɪɵ ɛɚɪ.

Ɇɵɫɚɥɵ: V * Vx wV x dx , WI W xy W xy dy , ɬɚԑɵ ɫɨɥ ɫɟɤiɥɞi.
x wx xy wy

Ԕɚɪɚɥɵɩ ɨɬɵɪԑɚɧ ɞɟɧɟ ɫɬɚɬɢɤɚɥɵԕ ɬɟɩɟ-ɬɟԙɞɿɤɬɟ ɬԝɪԑɚɧɞɵԕɬɚɧ, ɨɞɚɧ
ɛԧɥiɧiɩ ɚɥɵɧԑɚɧ ɷɥɟɦɟɧɬɚɪ ɩɚɪɚɥɥɟɥɟɩɢɩɟɞ ɬɟ ɬɟɩɟ-ɬɟԙɞɿɤɬɟ ɛɨɥɚɞɵ.
ɋɨɧɞɵԕɬɚɧ ɫɬɚɬɢɤɚɧɵԙ ɚɥɬɵ ɬɟԙɞɟɭɿɧ ԕԝɪɚɦɵɡ. Ɍɟԙɞɟɭɥɟɪɞi ԕԝɪԑɚɧ ɤɟɡɞɟ,
ɩɚɪɚɥɥɟɥɟɩɢɩɟɞɬiԙ ԧɡ ɫɚɥɦɚԑɵɧ (ɤԧɥɟɦɞiɤ ɫɚɥɦɚԕ ɤԛɲi) ԝɦɵɬɩɚɭ ɤɟɪɟɤ.
Ʉԧɥɟɦɞɿɤ ɤԛɲɬɿԙ ɨɫɶɬɟɪɝɟ ɩɪɨɟɤɰɢɹɥɚɪɵɧ X, ɍ, Z ԥɪiɩɬɟɪiɦɟɧ
ɛɟɥɝɿɥɟɣɦɿɡ, ɚɥ ɦɚɬɟɪɢɚɥɞɵԙ ɦɟɧɲiɤɬɿ ɫɚɥɦɚԑɵɧ ȡ ɚɪԕɵɥɵ ɛɟɥɝiɥɟɣɦɿɡ.
ɉɚɪɚɥɥɟɥɟɩɢɩɟɞɬiԙ ɤԧɥɟɦɞiɤ ɫɚɥɦɚԑɵɧɵԙ ɩɪɨɟɤɰɢɹɥɚɪɵ ɏǜȡǜdV, ɍǜȡǜdV
ɠɽɧɟ ZǜȡǜdV ɚɪԕɵɥɵ ɬɚɛɵɥɚɞɵ. Ȼԝɥ ɠɟɪɞɟɝi dV=dɯdɭdz ɷɥɟɦɟɧɬɚɪ
ɩɚɪɚɥɥɟɥɟɩɢɩɟɞɬiԙ ɤԧɥɟɦi.
ɋɬɚɬɢɤɚɧɵԙ ɤɟԙɿɫɬɿɤɬɟɝɿ ɚɥɬɵ ɬɟԙɞɟɭɥɟɪɿ:

6ɯ=0; 6Ɇɏ=0; (8.1)
6ɭ=0; 6Ɇɍ=0;
6z=0; 6Ɇz=0.
Ȼɿɪɿɧɲɿ ɬɟԙɞɟɭɞɿ ԕԝɪɭ ԛɲɿɧ, ɯ ɨɫɿɧɟ ɩɚɪɚɥɥɟɥɶ ɤԛɲɬɟɪɞɿ ɠɟɤɟɥɟɩ
ɤԧɪɫɟɬɟɣɿɤ (101-ɫɭɪɟɬ).

101-ɫɭɪɟɬ

6ɯ=0 ɬɟԙɞɟɭiɧ ԕԝɪɚɣɵԕ:

§¨V x wV x dx ·¸dydz V x dydz ©¨¨§W xy wW xy dy ·¹¸¸dxdz W xy dxdz ¨§W xz wW xz dz ¸·dxdy W xz dxdy
© wx ¹ wy © wz ¹

x ˜ U ˜ dx ˜ dy ˜ dz 0.

ɀɚԕɲɚɥɚɪɞɵ ɚɲɵɩ, ԝԕɫɚɫ ɦԛɲɟɥɟɪɞɿ ɠɢɧɚԕɬɚɩ, ɷɥɟɦɟɧɬɚɪ
ɩɚɪɚɥɥɟɥɟɩɢɩɟɞɬɿԙ ɤԧɥɟɦɿɧɟ (dV= dɯ dɭ dz) ɛԧɥɝɟɧɧɟɧ ɤɟɣɿɧ:

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