Page 226 - index

38-ɫɭɪɟɬ

dA Fxdx Fy dy Fz dz . (124ɚ)

3.2. ɇΟɤɬɟɧɿΝ ɲɟɤɬɿ ɨɪɵɧ ɚɭɵɫɬɵɪɭɵɧɞɚΕɵ ɤΟɲɬɿΝ ɠΡɦɵɫɵ.

ɇԛɤɬɟɧɿԙ ɲɟɤɬɿ ɨɪɵɧ ɚɭɵɫɬɵɪɭɵɧɞɚԑɵ ɤԛɲɬɿԙ ɠԝɦɵɫɵ ɞɟɩ ɷɥɟɦɟɧɬɚɪ

ɠԝɦɵɫɬɚɧ ԕɢɫɵԕɬɵԙ ɞɨԑɚɫɵɧɵԙ ɛɨɣɵɦɟɧ ɚɥɵɧԑɚɧ ԕɢɫɵԕɫɵɡɵԕɬɵ ɢɧɬɟɝɪɚɥ
ɚɬɚɥɚɞɵ, ɹԑɧɢ:

M2 F& ˜ dr* M2
³ ³A (125)
(Fx dx Fy dy Fz dz) .

M1 M1

3.3. ɇΟɤɬɟɧɿΝ ɬΟɡɭ ɫɵɡɵΙɬɵ ΙɨɡΕɚɥɵɫɵɧɞɚΕɵ ɬΡɪɚΙɬɵ ɤΟɲɬɿΝ

o

ɠΡɦɵɫɵ. Ɇɨɞɭɥɿ ɠԥɧɟ ɛɚԑɵɬɵ ɬԝɪɚԕɬɵ F ɤԛɲɿɧɿԙ ԥɫɟɪɿɧɟɧ, ɧԛɤɬɟ Ox

ɨɫɿɧɿԙ ɛɨɣɵɦɟɧ ԕɨɡԑɚɥɵɩ, M1 ɨɪɧɵɧɚɧ M 2 ɨɪɧɵɧɚ ɚɭɵɫɫɵɧ (39-ɫɭɪɟɬ).

39-ɫɭɪɟɬ
ɋɨԙԑɵ 125-ɮɨɪɦɭɥɚɧɵ ɩɚɣɞɚɥɚɧɵɩ, ɨɫɵ ɤԛɲɬɿԙ ɠԝɦɵɫɵɧ ɬɚɛɚɦɵɡ. Ɉɥ
ԛɲɿɧ, ɚɥɞɵɦɟɧ ɤԛɲɬɿԙ ɩɪɨɟɤɰɢɹɫɵɧ ɬɚɭɵɩ ɚɥɚɣɵԕ, ɹԑɧɢ:

Fx F cosM .
Ɏɨɪɦɭɥɚԑɚ ԕɨɣԑɚɧɧɚɧ ɤɟɣɿɧ:

x2

A ³ F cosM ˜ dx F cosM ˜ (x2 x1) F ˜ S ˜ cosM . Ⱦɟɦɟɤ A F ˜ S ˜ cosM . (126)
x1

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