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Механика.Методика решения задач

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Ƚɥɚɜɚ 1. Ʉɢɧɟɦɚɬɢɤɚ ɦɚɬɟɪɢɚɥɶɧɨɣ ɬɨɱɤɢ ɢ ɩɪɨɫɬɟɣɲɢɯ ɫɢɫɬɟɦ

31

Ⱦɥɹ ɪɟɲɟɧɢɹ ɡɚɞɚɱɢ ɡɚɩɢɫɚɧɧɵɟ ɭɪɚɜɧɟɧɢɹ ɧɟɨɛɯɨɞɢɦɨ ɞɨɩɨɥɧɢɬɶ ɨɩɪɟɞɟɥɟɧɢɹɦɢ (1.24) ɢ ɜɵɪɚɠɟɧɢɹɦɢ (1.25) ɞɥɹ ɢɧɬɟɪɟɫɭɸɳɢɯ ɧɚɫ ɜɟɥɢɱɢɧ, ɩɪɢɜɟɞɟɧɧɵɦɢ ɜ ɩ. 1.1.

III. ɇɚɣɞɟɦ ɡɚɤɨɧɵ ɢɡɦɟɧɟɧɢɹ ɫɤɨɪɨɫɬɢ ɝɪɭɡɚ ɢ ɟɝɨ ɭɫɤɨɪɟɧɢɹ ɜ ɩɪɨɟɤɰɢɹɯ ɧɚ ɨɫɢ ɞɟɤɚɪɬɨɜɨɣ ɫɢɫɬɟɦɵ ɤɨɨɪɞɢɧɚɬ, ɢɫɩɨɥɶɡɭɹ

ɨɩɪɟɞɟɥɟɧɢɹ (1.6) ɢ (1.12):

 

Xx

dx

 

2bt , Xy

0 ;

(1.82)

dt

 

 

 

 

ax

dX

2b , ay

0 .

(1.83)

d t

 

 

 

 

Ɍɨɱɤɢ ɨɛɨɞɚ ɜɚɥɚ ɫɨɜɟɪɲɚɸɬ ɧɟɪɚɜɧɨɦɟɪɧɨɟ ɞɜɢɠɟɧɢɟ ɩɨ ɨɤɪɭɠɧɨɫɬɢ, ɩɪɢɱɟɦ ɦɨɞɭɥɶ ɢɯ ɫɤɨɪɨɫɬɢ (ɩɨɫɤɨɥɶɤɭ ɧɢɬɶ ɧɟɪɚɫɬɹɠɢɦɚ ɢ ɧɟ ɩɪɨɫɤɚɥɶɡɵɜɚɟɬ ɩɨ ɩɨɜɟɪɯɧɨɫɬɢ ɨɛɨɞɚ) ɜ ɤɚɠɞɵɣ ɦɨɦɟɧɬ ɜɪɟɦɟɧɢ ɪɚɜɟɧ ɦɨɞɭɥɸ ɫɤɨɪɨɫɬɢ ɝɪɭɡɚ, ɩɨɷɬɨɦɭ, ɢɫɩɨɥɶɡɭɹ (1.22) ɞɥɹ ɭɝɥɨɜɨɣ ɫɤɨɪɨɫɬɢ Z ɢ ɭɝɥɨɜɨɝɨ ɭɫɤɨɪɟɧɢɹ E, ɩɨɥɭɱɚɟɦ:

Z

Xx

2bt

,

(1.84)

R

 

R

 

 

 

 

 

E

d Z

 

 

2b

.

(1.85)

d t

 

 

 

R

 

 

 

ɉɨɫɤɨɥɶɤɭ ɩɪɨɟɤɰɢɹ ɭɫɤɨɪɟɧɢɹ ɝɪɭɡɚ ɧɚ ɨɫɶ X ɪɚɜɧɚ ɬɚɧɝɟɧɰɢɚɥɶɧɨɣ ɩɪɨɟɤɰɢɢ ɭɫɤɨɪɟɧɢɹ ɬɨɱɟɤ ɨɛɨɞɚ, ɬɨ:

aW

2b .

 

 

 

 

 

 

 

 

 

(1.86)

ɇɨɪɦɚɥɶɧɭɸ ɩɪɨɟɤɰɢɸ ɭɫɤɨɪɟɧɢɹ ɨɩɪɟɞɟɥɢɦ, ɢɫɩɨɥɶɡɭɹ

(1.22):

 

 

 

 

 

 

 

 

 

 

 

an

X2

 

4b2t

2

.

 

 

 

 

(1.87)

R

 

 

R

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Ɇɨɞɭɥɶ ɩɨɥɧɨɝɨ ɭɫɤɨɪɟɧɢɹ ɩɪɨɢɡɜɨɥɶɧɨɣ ɬɨɱɤɢ A ɧɚ ɨɛɨɞɟ

ɤɨɥɟɫɚ ɧɚɣɞɟɦ ɢɡ ɫɨɨɬɧɨɲɟɧɢɹ (1.20):

 

a

a2 a2

2b

4b2t 4

1 .

(1.88)

 

 

n

 

 

W

 

 

R2

 

 

 

 

 

 

 

 

 

 

 

 

 

Ɂɚɤɨɧ ɞɜɢɠɟɧɢɹ ɩɪɨɢɡɜɨɥɶɧɨɣ ɬɨɱɤɢ A ɧɚ ɨɛɨɞɟ ɜɚɥɚ ɡɚɩɢ-

ɲɟɦ ɜ ɩɨɥɹɪɧɨɣ ɫɢɫɬɟɦɟ ɤɨɨɪɞɢɧɚɬ:

 

M(t)

M0

 

E t 2

 

M0

bt 2

 

,

(1.89)

2

 

R

 

 

 

 

 

 

 

 

 

 

 

ɝɞɟ M0 – ɧɚɱɚɥɶɧɨɟ ɡɧɚɱɟɧɢɟ ɭɝɥɨɜɨɣ ɤɨɨɪɞɢɧɚɬɵ ɬɨɱɤɢ A ɜ ɜɵɛɪɚɧɧɨɣ ɩɨɥɹɪɧɨɣ ɫɢɫɬɟɦɟ ɤɨɨɪɞɢɧɚɬ.

32 ɆȿɏȺɇɂɄȺ. ɆȿɌɈȾɂɄȺ Ɋȿɒȿɇɂə ɁȺȾȺɑ

Ɂɚɞɚɱɚ 1.9

(ɇɚ ɤɢɧɟɦɚɬɢɤɭ ɦɚɬɟɪɢɚɥɶɧɨɣ ɬɨɱɤɢ)

Ɂɚɤɨɧ ɞɜɢɠɟɧɢɹ ɞɜɢɠɭɳɟɣɫɹ ɜ ɩɥɨɫɤɨɫɬɢ ɦɚɬɟɪɢɚɥɶɧɨɣ ɬɨɱɤɢ, ɡɚɞɚɧɧɵɣ ɜ ɩɨɥɹɪɧɨɣ ɫɢɫɬɟɦɟ ɤɨɨɪɞɢɧɚɬ, ɢɦɟɟɬ ɫɥɟɞɭɸɳɢɣ

ɜɢɞ: r = r(t), ij = ij(t). Ɉɩɪɟɞɟɥɢɬɶ ɡɚ-

 

 

 

ɤɨɧɵ ɢɡɦɟɧɟɧɢɹ ɩɪɨɟɤɰɢɣ ɫɤɨɪɨɫɬɢ ɢ

Y

 

 

ɭɫɤɨɪɟɧɢɹ ɦɚɬɟɪɢɚɥɶɧɨɣ ɬɨɱɤɢ ɧɚ

 

eM

er

ɧɚɩɪɚɜɥɟɧɢɹ, ɡɚɞɚɜɚɟɦɵɟ ɨɪɬɚɦɢ ɞɟ-

 

ɤɚɪɬɨɜɨɣ ɢ ɩɨɥɹɪɧɨɣ ɫɢɫɬɟɦ ɤɨɨɪɞɢ-

 

r

M

ɧɚɬ, ɠɟɫɬɤɨ ɫɜɹɡɚɧɧɵɯ ɫ ɬɟɥɨɦ ɨɬɫɱɟ-

 

j

 

 

ɬɚ. ɇɚɱɚɥɨ ɞɟɤɚɪɬɨɜɨɣ ɫɢɫɬɟɦɵ ɤɨɨɪ-

M

 

ɞɢɧɚɬ ɫɨɜɩɚɞɚɟɬ ɫ ɩɨɥɸɫɨɦ ɩɨɥɹɪɧɨɣ

 

 

 

 

 

ɫɢɫɬɟɦɵ, ɚ ɨɫɶ X ɞɟɤɚɪɬɨɜɨɣ ɫɢɫɬɟɦɵ

O

i

X

ɧɚɩɪɚɜɥɟɧɚ ɜɞɨɥɶ ɩɨɥɹɪɧɨɣ ɨɫɢ (ɫɦ.

 

Ɋɢɫ. 1.14

ɪɢɫ. 1.14).

 

Ɋɟɲɟɧɢɟ

 

 

 

I. ȼɵɛɟɪɟɦ ɨɫɶ Y ɞɟɤɚɪɬɨɜɨɣ ɫɢɫɬɟɦɵ ɤɨɨɪɞɢɧɚɬ ɬɚɤ, ɱɬɨɛɵ ɩɥɨɫɤɨɫɬɶ XY ɫɨɜɩɚɞɚɥɚ ɫ ɩɥɨɫɤɨɫɬɶɸ, ɜ ɤɨɬɨɪɨɣ ɞɜɢɠɟɬɫɹ ɦɚɬɟɪɢɚɥɶɧɚɹ ɬɨɱɤɚ M (ɪɢɫ. 1.14). Ⱦɥɹ ɪɟɲɟɧɢɹ ɡɚɞɚɱɢ ɢɫɩɨɥɶɡɭɟɦ ɞɜɟ ɫɢɫɬɟɦɵ ɤɨɨɪɞɢɧɚɬ – ɞɟɤɚɪɬɨɜɭ ɫɢɫɬɟɦɭ ɤɨɨɪɞɢɧɚɬ XOY c ɨɪɬɚɦɢ i ɢ j , ɢ ɩɨɥɹɪɧɭɸ, ɨɪɬɵ ɤɨɬɨɪɨɣ er ɢ eM ɢɡɨɛɪɚɠɟɧɵ ɧɚ ɪɢɫ. 1.14.

Ɂɚɦɟɬɢɦ, ɱɬɨ ɩɪɢ ɞɜɢɠɟɧɢɢ ɦɚɬɟɪɢɚɥɶɧɨɣ ɬɨɱɤɢ ɩɪɨɢɫɯɨɞɢɬ ɢɡɦɟɧɟɧɢɟ ɨɪɢɟɧɬɚɰɢɢ ɨɪɬɨɜ ɩɨɥɹɪɧɨɣ ɫɢɫɬɟɦɵ er ɢ eM , ɜ ɬɨ ɜɪɟɦɹ ɤɚɤ

ɨɪɬɵ ɞɟɤɚɪɬɨɜɨɣ ɫɢɫɬɟɦɵ ɤɨɨɪɞɢɧɚɬ i ɢ j ɧɟ ɢɡɦɟɧɹɸɬ ɫɜɨɟɝɨ ɧɚ-

ɩɪɚɜɥɟɧɢɹ.

II, III. Ɂɚɤɨɧ ɞɜɢɠɟɧɢɹ ɦɚɬɟɪɢɚɥɶɧɨɣ ɬɨɱɤɢ, ɡɚɞɚɧɧɵɣ ɜ ɩɨɥɹɪɧɨɣ ɫɢɫɬɟɦɟ, ɡɚɩɢɲɟɦ ɜ ɞɟɤɚɪɬɨɜɨɣ ɫɢɫɬɟɦɟ ɤɨɨɪɞɢɧɚɬ XOY:

x(t) r(t) cosM(t),

(1.90)

y(t) r(t)sinM(t).

Ⱦɢɮɮɟɪɟɧɰɢɪɭɹ ɡɚɤɨɧ ɞɜɢɠɟɧɢɹ (1.90) ɩɨ ɜɪɟɦɟɧɢ, ɩɨɥɭɱɚɟɦ ɢɫɤɨɦɵɟ ɡɚɤɨɧɵ ɢɡɦɟɧɟɧɢɹ ɩɪɨɟɤɰɢɣ ɫɤɨɪɨɫɬɢ ɦɚɬɟɪɢɚɥɶɧɨɣ ɬɨɱɤɢ

ɢ ɟɟ ɭɫɤɨɪɟɧɢɹ ɜ ɞɟɤɚɪɬɨɜɨɣ ɫɢɫɬɟɦɟ ɤɨɨɪɞɢɧɚɬ:

 

Xx

 

 

 

 

x

r cosM rM sinM,

(1.91)

X y

 

 

 

y

r sinM rM cosM;

 

Ƚɥɚɜɚ 1. Ʉɢɧɟɦɚɬɢɤɚ ɦɚɬɟɪɢɚɥɶɧɨɣ ɬɨɱɤɢ ɢ ɩɪɨɫɬɟɣɲɢɯ ɫɢɫɬɟɦ

33

ax

 

 

2

 

 

 

Xx

(r

rM

) cosM (2rM

rM) sinM,

(1.92)

a y

 

 

2

 

 

 

X y

(r

rM

) sinM (2rM

rM) cosM.

 

ȼ ɮɨɪɦɭɥɚɯ (1.92), (1.92) ɢ ɞɚɥɟɟ ɞɥɹ ɤɪɚɬɤɨɫɬɢ ɨɩɭɫɬɢɦ ɡɚɩɢɫɶ ɡɚɜɢɫɢɦɨɫɬɢ ɤɢɧɟɦɚɬɢɱɟɫɤɢɯ ɜɟɥɢɱɢɧ ɨɬ ɜɪɟɦɟɧɢ.

ɉɪɨɟɤɰɢɢ ɫɤɨɪɨɫɬɢ ɢ ɭɫɤɨɪɟɧɢɹ ɦɚɬɟɪɢɚɥɶɧɨɣ ɬɨɱɤɢ ɜ ɩɨɥɹɪɧɨɣ ɫɢɫɬɟɦɟ ɤɨɨɪɞɢɧɚɬ ɧɚɯɨɞɢɦ ɞɜɭɦɹ ɫɩɨɫɨɛɚɦɢ.

1 ɫɩɨɫɨɛ. ɋɤɨɪɨɫɬɶ ɢ ɭɫɤɨɪɟɧɢɟ ɦɚɬɟɪɢɚɥɶɧɨɣ ɬɨɱɤɢ ɜ ɩɨɥɹɪ-

ɧɨɣ ɫɢɫɬɟɦɟ ɤɨɨɪɞɢɧɚɬ ɡɚɩɢɫɵɜɚɸɬɫɹ ɜ ɜɢɞɟ:

 

ȣ

Xr er XMeM ,

(1.93)

a

ar er aMeM .

(1.94)

ɋɥɟɞɨɜɚɬɟɥɶɧɨ, ɩɪɨɟɤɰɢɢ ɫɤɨɪɨɫɬɢ ɢ ɭɫɤɨɪɟɧɢɹ ɦɚɬɟɪɢɚɥɶɧɨɣ ɬɨɱɤɢ ɧɚ ɧɚɩɪɚɜɥɟɧɢɹ, ɡɚɞɚɜɚɟɦɵɟ ɨɪɬɚɦɢ ɪɚɫɫɦɚɬɪɢɜɚɟɦɵɯ ɫɢɫɬɟɦ ɤɨɨɪɞɢɧɚɬ, ɫɜɹɡɚɧɵ ɫɨɨɬɧɨɲɟɧɢɹɦɢ:

Xx

ȣ i

Xr er i XM eM i

Xr cosM XM sin M,

(1.95)

Xy

ȣ j

Xr er j XM eM j

Xr sin M XM cosM;

 

ax

a i

ar er i aM eM i

ar cosM aM sinM,

(1.96)

ay

a j

ar er j aMeM j

ar sin M aM cosM.

 

ɋɪɚɜɧɢɜɚɹ ɫɨɨɬɧɨɲɟɧɢɹ (1.90) ɢ (1.95), ɚ ɬɚɤɠɟ (1.91) ɢ (1.96), ɩɨɥɭɱɢɦ ɢɫɤɨɦɵɟ ɩɪɨɟɤɰɢɢ ɫɤɨɪɨɫɬɢ ɢ ɭɫɤɨɪɟɧɢɹ ɦɚɬɟɪɢɚɥɶɧɨɣ ɬɨɱɤɢ ɜ ɩɨɥɹɪɧɨɣ ɫɢɫɬɟɦɟ ɤɨɨɪɞɢɧɚɬ:

Xr

 

 

 

 

r,

 

 

(1.97)

XM

 

 

 

rM;

 

 

 

ar

 

2

,

 

r rM

(1.98)

aM

 

 

 

2rM

rM.

 

2 ɫɩɨɫɨɛ. Ɂɚɩɢɲɟɦ ɪɚɞɢɭɫ-ɜɟɤɬɨɪ ɦɚɬɟɪɢɚɥɶɧɨɣ ɬɨɱɤɢ ɜ ɩɨɥɹɪɧɨɣ ɫɢɫɬɟɦɟ ɤɨɨɪɞɢɧɚɬ:

r rer .

(1.99)

ɉɨɫɤɨɥɶɤɭ ɩɪɢ ɞɜɢɠɟɧɢɢ ɦɚɬɟɪɢɚɥɶɧɨɣ ɬɨɱɤɢ ɩɪɨɢɫɯɨɞɢɬ ɢɡɦɟɧɟɧɢɟ ɨɪɢɟɧɬɚɰɢɢ ɨɪɬɨɜ ɩɨɥɹɪɧɨɣ ɫɢɫɬɟɦɵ er ɢ eM , ɧɚɣɞɟɦ

ɫɤɨɪɨɫɬɶ ɢɯ ɢɡɦɟɧɟɧɢɹ (ɫɦ. ɪɢɫ. 1.15):

 

 

 

er

MeM ,

(1.100)

 

 

eM

Mer.

 

34 ɆȿɏȺɇɂɄȺ. ɆȿɌɈȾɂɄȺ Ɋȿɒȿɇɂə ɁȺȾȺɑ

deM

e

der

 

 

dM

r

 

 

 

dM

 

 

O

X

 

 

Ɋɢɫ. 1.15

Ɍɟɩɟɪɶ ɞɥɹ ɧɚɯɨɠɞɟɧɢɹ ɫɤɨɪɨɫɬɢ ɢ ɭɫɤɨɪɟɧɢɹ ɬɨɱɤɢ ɜ ɬɨɣ ɠɟ ɫɢɫɬɟɦɟ ɤɨɨɪɞɢɧɚɬ ɧɟɨɛɯɨɞɢɦɨ ɩɪɨɞɢɮɮɟɪɟɧɰɢɪɨɜɚɬɶ ɪɚɞɢɭɫɜɟɤɬɨɪ (1.99) ɩɨ ɜɪɟɦɟɧɢ ɫ ɭɱɟɬɨɦ (1.100):

 

 

 

 

 

 

 

,

(1.101)

ȣ r

rer

rer

rer

rMeM

 

 

 

 

 

 

 

 

 

a ȣ

rer

rer

rMeM rMeM rMeM

 

2

)er

 

 

 

 

(1.102)

(r

rM

 

(2rM

rM)eM .

ȼ ɫɨɨɬɜɟɬɫɬɜɢɢ ɫ (1.101) ɢ (1.102) ɢɫɤɨɦɵɟ ɩɪɨɟɤɰɢɢ ɫɤɨɪɨɫɬɢ ɢ ɭɫɤɨɪɟɧɢɹ ɦɚɬɟɪɢɚɥɶɧɨɣ ɬɨɱɤɢ ɜ ɩɨɥɹɪɧɨɣ ɫɢɫɬɟɦɟ ɤɨɨɪɞɢɧɚɬ ɪɚɜɧɵ:

Xr

 

 

 

 

r,

 

 

(1.103)

XM

 

;

 

rM

 

 

ar

 

2

 

r rM

,

(1.104)

aM

 

 

 

2rM rM.

 

Ʉɚɤ ɜɢɞɢɦ, ɨɛɚ ɫɩɨɫɨɛɚ ɪɟɲɟɧɢɹ ɞɚɸɬ ɨɞɢɧɚɤɨɜɵɣ ɪɟɡɭɥɶɬɚɬ.

Ɂɚɞɚɱɚ 1.10

(ɇɚ ɤɢɧɟɦɚɬɢɤɭ ɦɚɬɟɪɢɚɥɶɧɨɣ ɬɨɱɤɢ)

Ⱦɜɢɠɟɧɢɟ ɦɚɬɟɪɢɚɥɶɧɨɣ ɬɨɱɤɢ ɜ ɩɨɥɹɪɧɨɣ ɫɢɫɬɟɦɟ ɤɨɨɪɞɢɧɚɬ ɡɚɞɚɟɬɫɹ ɜɡɚɢɦɨɫɜɹɡɶɸ ɩɨɥɹɪɧɵɯ ɤɨɨɪɞɢɧɚɬ r(M) 2a(1 cosM) , ɩɪɢ ɷɬɨɦ ɩɨɥɹɪɧɵɣ ɭɝɨɥ ɜɨɡɪɚɫɬɚɟɬ ɥɢɧɟɣɧɨ ɜɨ

ɜɪɟɦɟɧɢ M(t) bt . Ɉɩɪɟɞɟɥɢɬɶ ɡɚɜɢɫɢɦɨɫɬɶ ɦɨɞɭɥɹ ɫɤɨɪɨɫɬɢ ɢ ɦɨɞɭɥɹ ɭɫɤɨɪɟɧɢɹ ɦɚɬɟɪɢɚɥɶɧɨɣ ɬɨɱɤɢ ɨɬ ɜɪɟɦɟɧɢ.

Ɋɟɲɟɧɢɟ

I. Ɋɟɲɚɟɦ ɡɚɞɚɱɭ ɜ ɡɚɞɚɧɧɨɣ ɩɨɥɹɪɧɨɣ ɫɢɫɬɟɦɟ ɤɨɨɪɞɢɧɚɬ. Ɂɚɦɟɬɢɦ, ɱɬɨ ɦɚɬɟɪɢɚɥɶɧɚɹ ɬɨɱɤɚ M ɞɜɢɠɟɬɫɹ ɩɨ ɡɚɦɤɧɭɬɨɣ ɬɪɚɟɤ-

Ƚɥɚɜɚ 1. Ʉɢɧɟɦɚɬɢɤɚ ɦɚɬɟɪɢɚɥɶɧɨɣ ɬɨɱɤɢ ɢ ɩɪɨɫɬɟɣɲɢɯ ɫɢɫɬɟɦ

35

ɬɨɪɢɢ, ɩɟɪɢɨɞɢɱɟɫɤɢ, ɫ ɩɟɪɢɨɞɨɦ

 

 

 

2S

 

 

 

 

 

 

 

 

ȣ(t)

 

b , ɜɨɡɜɪɚɳɚɹɫɶ ɜ ɬɭ

ɠɟ

ɬɨɱɤɭ

 

 

 

M

 

ɩɪɨɫɬɪɚɧɫɬɜɚ (ɫɦ. ɪɢɫ. 1.16).

a(tk )

r(t)

 

II. Ɉɩɪɟɞɟɥɢɦ ɡɚɤɨɧ ɢɡɦɟɧɟ-

M(t)

 

ɧɢɹ ɩɪɨɟɤɰɢɣ ɫɤɨɪɨɫɬɢ ɢ ɭɫɤɨɪɟ-

 

O

X

ɧɢɹ ɦɚɬɟɪɢɚɥɶɧɨɣ ɬɨɱɤɢ ɜ ɩɨɥɹɪ-

 

ɧɨɣ ɫɢɫɬɟɦɟ ɤɨɨɪɞɢɧɚɬ, ɜɨɫɩɨɥɶ-

 

 

 

ɡɨɜɚɜɲɢɫɶ

ɮɨɪɦɭɥɚɦɢ

(1.103) ɢ

 

 

 

(1.104), ɩɨɥɭɱɟɧɧɵɦɢ ɜ ɩɪɟɞɵɞɭ-

 

Ɋɢɫ. 1.16

 

ɳɟɣ ɡɚɞɚɱɟ:

2a sinMM

 

2ab sinM,

 

 

 

Xr

r

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(1.105)

XM

 

2a(1 cosM)b;

 

 

rM

 

 

 

ar

 

2

2ab

2

(2 cosM 1),

 

 

 

r rM

 

 

 

(1.106)

aM

 

 

4ab

2

sinM.

 

 

 

 

 

2rM rM

 

 

 

 

Ɍɨɝɞɚ ɢɫɤɨɦɵɟ ɦɨɞɭɥɢ ɫɤɨɪɨɫɬɢ ɢ ɭɫɤɨɪɟɧɢɹ ɦɚɬɟɪɢɚɥɶɧɨɣ ɬɨɱɤɢ ɪɚɜɧɵ:

X

X2

X2

2ab

2 2 cos(bt) ,

(1.107)

 

r

M

 

 

 

a

a2

a2

2ab2

5 4 cos(bt).

(1.108)

 

r

M

 

 

 

 

Ɂɚɦɟɬɢɦ, ɱɬɨ ɦɚɬɟɪɢɚɥɶɧɚɹ ɬɨɱɤɚ ɜ ɦɨɦɟɧɬɵ ɜɪɟɦɟɧɢ

tk

(2k 1) S

(ɝɞɟ k = 0, 1, 2, ...) ɧɚɯɨɞɢɬɫɹ ɜ ɧɚɱɚɥɟ (ɩɨɥɸɫɟ) ɩɨ-

 

b

 

ɥɹɪɧɨɣ ɫɢɫɬɟɦɵ ɤɨɨɪɞɢɧɚɬ, ɢɦɟɟɬ ɧɭɥɟɜɭɸ ɫɤɨɪɨɫɬɶ, ɚ ɭɫɤɨɪɟɧɢɟ, ɩɨ ɦɨɞɭɥɸ ɪɚɜɧɨɟ a(tk ) 2ab2 , ɧɚɩɪɚɜɥɟɧɨ ɩɪɨɬɢɜɨɩɨɥɨɠɧɨ ɩɨɥɹɪɧɨɣ ɨɫɢ.

Ɂɚɞɚɱɚ 1.11

(ɇɚ ɤɢɧɟɦɚɬɢɤɭ ɦɚɬɟɪɢɚɥɶɧɨɣ ɬɨɱɤɢ)

ɉɥɚɧɟɬɚ ɞɜɢɠɟɬɫɹ ɜɨɤɪɭɝ ɋɨɥɧɰɚ ɜ ɫɨɨɬɜɟɬɫɬɜɢɢ ɫ ɡɚɤɨɧɚɦɢ Ʉɟɩɥɟɪɚ ɩɨ ɷɥɥɢɩɬɢɱɟɫɤɨɣ ɬɪɚɟɤɬɨɪɢɢ r(1 e cosM) p . ɉɚɪɚɦɟɬɪ

ɷɥɥɢɩɫɚ p , ɷɤɫɰɟɧɬɪɢɫɢɬɟɬ e ɢ ɫɟɤɬɨɪɧɭɸ ɫɤɨɪɨɫɬɶ V ɫɱɢɬɚɬɶ ɡɚ-

ɞɚɧɧɵɦɢ. Ɉɩɪɟɞɟɥɢɬɶ ɩɪɨɟɤɰɢɢ ɭɫɤɨɪɟɧɢɹ ɩɥɚɧɟɬɵ ɜ ɡɚɜɢɫɢɦɨɫɬɢ ɨɬ ɤɨɨɪɞɢɧɚɬ r ɢ M ɩɨɥɹɪɧɨɣ ɫɢɫɬɟɦɵ.

36

ɆȿɏȺɇɂɄȺ. ɆȿɌɈȾɂɄȺ Ɋȿɒȿɇɂə ɁȺȾȺɑ

Ɋɟɲɟɧɢɟ

I. ɉɪɢ ɪɟɲɟɧɢɢ ɡɚɞɚɱɢ ɛɭɞɟɦ ɫɱɢɬɚɬɶ ɩɥɚɧɟɬɭ ɢ ɋɨɥɧɰɟ ɦɚɬɟɪɢɚɥɶɧɵɦɢ ɬɨɱɤɚɦɢ. ɋɨɝɥɚɫɧɨ ɩɟɪɜɨɦɭ ɡɚɤɨɧɭ Ʉɟɩɥɟɪɚ ɜɫɟ ɩɥɚɧɟɬɵ ɞɜɢɠɭɬɫɹ ɩɨ ɷɥɥɢɩɬɢɱɟɫɤɢɦ ɨɪɛɢɬɚɦ, ɩɪɢɱɟɦ ɋɨɥɧɰɟ ɧɚɯɨɞɢɬɫɹ ɜ ɨɞɧɨɦ ɢɡ ɮɨɤɭɫɨɜ ɷɥɥɢɩɫɚ O (ɫɦ. ɪɢɫ. 1.17).

 

rM't

 

 

r(t+ǻt)

r(t)

M(t)

 

O

X

Ɋɢɫ. 1.17

 

ȼ ɫɨɨɬɜɟɬɫɬɜɢɢ ɫ ɭɫɥɨɜɢɟɦ ɡɚɞɚɱɢ ɜɜɟɞɟɦ ɩɨɥɹɪɧɭɸ ɫɢɫɬɟɦɭ ɤɨɨɪɞɢɧɚɬ ɜ ɩɥɨɫɤɨɫɬɢ ɞɜɢɠɟɧɢɹ ɩɥɚɧɟɬɵ, ɩɨɥɸɫ ɤɨɬɨɪɨɣ ɫɨɜɩɚɞɚɟɬ ɫ ɋɨɥɧɰɟɦ, ɚ ɩɨɥɹɪɧɚɹ ɨɫɶ ɫɨɜɩɚɞɚɟɬ ɫ ɨɞɧɨɣ ɢɡ ɨɫɟɣ ɷɥɥɢɩɫɚ.

ɋɨɝɥɚɫɧɨ ɜɬɨɪɨɦɭ ɡɚɤɨɧɭ Ʉɟɩɥɟɪɚ ɫɟɤɬɨɪɧɚɹ ɫɤɨɪɨɫɬɶ V ɩɥɚɧɟɬɵ, ɪɚɜɧɚɹ ɫɤɨɪɨɫɬɢ ɢɡɦɟɧɟɧɢɹ ɩɥɨɳɚɞɢ, ɨɩɢɫɵɜɚɟɦɨɣ ɪɚɞɢ- ɭɫ-ɜɟɤɬɨɪɨɦ ɦɚɬɟɪɢɚɥɶɧɨɣ ɬɨɱɤɢ, ɩɪɟɞɫɬɚɜɥɹɸɳɢɦ ɩɥɚɧɟɬɭ, ɩɨɫɬɨɹɧɧɚ ɩɪɢ ɞɜɢɠɟɧɢɢ ɩɥɚɧɟɬɵ ɜɨɤɪɭɝ ɋɨɥɧɰɚ.

II. Ⱦɥɹ ɧɚɯɨɠɞɟɧɢɹ ɩɪɨɟɤɰɢɣ ɭɫɤɨɪɟɧɢɹ ɩɥɚɧɟɬɵ ɜ ɩɨɥɹɪɧɨɣ

ɫɢɫɬɟɦɟ ɤɨɨɪɞɢɧɚɬ ɜɨɫɩɨɥɶɡɭɟɦɫɹ ɮɨɪɦɭɥɚɦɢ (1.104):

 

ar

 

2

,

 

r rM

(1.109)

aM

 

 

 

2rM

rM.

 

ɉɨɫɤɨɥɶɤɭ ɜ ɭɪɚɜɧɟɧɢɹ (1.109) ɜɯɨɞɹɬ ɩɪɨɢɡɜɨɞɧɵɟ ɩɨɥɹɪɧɵɯ ɤɨɨɪɞɢɧɚɬ ɩɨ ɜɪɟɦɟɧɢ, ɞɨɩɨɥɧɢɦ ɷɬɭ ɫɢɫɬɟɦɭ ɭɪɚɜɧɟɧɢɟɦ ɬɪɚɟɤɬɨɪɢɢ ɩɥɚɧɟɬɵ ɢ ɜɵɪɚɠɟɧɢɟɦ ɞɥɹ ɟɟ ɫɟɤɬɨɪɧɨɣ ɫɤɨɪɨɫɬɢ V :

r(1 e cosM) p ,

(1.110)

V

1

2

(1.111)

 

2 r M .

III. ȼ ɫɨɨɬɜɟɬɫɬɜɢɢ ɫ ɭɫɥɨɜɢɟɦ ɡɚɞɚɱɢ ɫɟɤɬɨɪɧɚɹ ɫɤɨɪɨɫɬɶ V ɩɨɫɬɨɹɧɧɚ ɩɪɢ ɞɜɢɠɟɧɢɢ ɩɥɚɧɟɬɵ ɩɨ ɷɥɥɢɩɬɢɱɟɫɤɨɣ ɬɪɚɟɤɬɨɪɢɢ, ɩɨɷɬɨɦɭ ɟɟ ɩɪɨɢɡɜɨɞɧɚɹ ɩɨ ɜɪɟɦɟɧɢ ɪɚɜɧɚ ɧɭɥɸ:

Ƚɥɚɜɚ 1. Ʉɢɧɟɦɚɬɢɤɚ ɦɚɬɟɪɢɚɥɶɧɨɣ ɬɨɱɤɢ ɢ ɩɪɨɫɬɟɣɲɢɯ ɫɢɫɬɟɦ

37

 

 

1

 

2

 

 

 

2 r

0 .

 

(1.112)

V

rM

M

 

ɋɪɚɜɧɢɜɚɹ (1.112) ɫ ɜɵɪɚɠɟɧɢɟɦ (1.109)

ɞɥɹ ɩɪɨɟɤɰɢɢ ɭɫɤɨ-

ɪɟɧɢɹ aM ,

ɜɢɞɢɦ,

ɱɬɨ

aM 0 . ɋɥɟɞɨɜɚɬɟɥɶɧɨ,

ɭɫɤɨɪɟɧɢɟ ɜ ɥɸɛɨɣ

ɦɨɦɟɧɬ ɜɪɟɦɟɧɢ ɢɦɟɟɬ ɬɨɥɶɤɨ ɩɪɨɟɤɰɢɸ ar , ɤɨɬɨɪɚɹ ɜ ɫɨɨɬɜɟɬɫɬ-

ɜɢɢ ɫ (1.109) ɹɜɥɹɟɬɫɹ ɮɭɧɤɰɢɟɣ ɩɪɨɢɡɜɨɞɧɵɯ ɩɨɥɹɪɧɵɯ ɤɨɨɪɞɢɧɚɬ ɩɨ ɜɪɟɦɟɧɢ.

ɉɪɨɞɢɮɮɟɪɟɧɰɢɪɭɟɦ ɨɛɟ ɱɚɫɬɢ ɭɪɚɜɧɟɧɢɹ ɬɪɚɟɤɬɨɪɢɢ (1.110)

ɩɨ ɜɪɟɦɟɧɢ:

 

(1.113)

 

 

r(1

e cosM) re sinM M

0 .

ɂɫɩɨɥɶɡɭɹ ɭɪɚɜɧɟɧɢɟ ɬɪɚɟɤɬɨɪɢɢ (1.110) ɢ ɜɵɪɚɠɟɧɢɟ ɞɥɹ

ɫɟɤɬɨɪɧɨɣ ɫɤɨɪɨɫɬɢ (1.111), ɩɪɟɨɛɪɚɡɭɟɦ (1.113) ɤ ɜɢɞɭ:

 

 

 

0 .

 

(1.114)

rp 2Ve sinM

 

ɉɪɨɞɢɮɮɟɪɟɧɰɢɪɭɟɦ ɬɟɩɟɪɶ ɨɛɟ ɱɚɫɬɢ ɭɪɚɜɧɟɧɢɹ (1.114) ɩɨ

ɜɪɟɦɟɧɢ

 

0 .

 

(1.115)

 

 

r p 2Ve cosM M

 

Ɉɩɹɬɶ ɜɨɫɩɨɥɶɡɭɟɦɫɹ ɭɪɚɜɧɟɧɢɟɦ ɬɪɚɟɤɬɨɪɢɢ (1.110) ɢ ɜɵɪɚɠɟɧɢɟɦ ɞɥɹ ɫɟɤɬɨɪɧɨɣ ɫɤɨɪɨɫɬɢ (1.111) ɞɥɹ ɢɫɤɥɸɱɟɧɢɹ cosM ɢ M

ɢɡ (1.115):

r p

 

2V

 

2 r p

 

 

 

 

 

 

 

 

 

 

 

 

 

 

er

r 2

 

r3

0 .

(1.116)

rp 2Ve

rp 4V

 

ȼ ɪɟɡɭɥɶɬɚɬɟ ɧɚɯɨɞɢɦ:

r 4V 2 r p . (1.117) r3 p

Ⱦɥɹ ɧɚɯɨɠɞɟɧɢɹ ɢɫɤɨɦɨɣ ɩɪɨɟɤɰɢɢ ɭɫɤɨɪɟɧɢɹ ɩɥɚɧɟɬɵ ar , ɤɚɤ ɮɭɧɤɰɢɢ ɬɨɥɶɤɨ ɤɨɨɪɞɢɧɚɬ ɩɨɥɹɪɧɨɣ ɫɢɫɬɟɦɵ, ɩɨɞɫɬɚɜɢɦ r

 

 

2V

 

(ɫɦ. (1.111)) ɜ ɜɵɪɚɠɟɧɢɟ (1.109):

 

 

r 2

 

(1.116) ɢ M

 

 

 

2

 

2 r p

r

4V 2

 

4V 2

 

 

 

 

 

 

 

 

 

4V

 

r3 p

r 4

r 2 p .

(1.118)

ar r

rM

 

Ɍɚɤɢɦ ɨɛɪɚɡɨɦ, ɭɫɤɨɪɟɧɢɟ ɩɥɚɧɟɬɵ, ɞɜɢɠɭɳɟɣɫɹ ɩɨ ɷɥɥɢɩɬɢɱɟɫɤɨɣ ɬɪɚɟɤɬɨɪɢɢ, ɧɚɩɪɚɜɥɟɧɨ ɤ ɋɨɥɧɰɭ, ɧɟ ɡɚɜɢɫɢɬ ɨɬ ɩɨɥɹɪɧɨɝɨ ɭɝɥɚ M ɢ ɨɛɪɚɬɧɨ ɩɪɨɩɨɪɰɢɨɧɚɥɶɧɨ ɤɜɚɞɪɚɬɭ ɪɚɫɫɬɨɹɧɢɹ ɞɨ ɋɨɥɧ-

ɰɚ:

38

 

 

 

ɆȿɏȺɇɂɄȺ. ɆȿɌɈȾɂɄȺ Ɋȿɒȿɇɂə ɁȺȾȺɑ

ar

 

4V 2

,

r

2p

 

 

(1.119)

aM

0.

 

 

Ɂɚɞɚɱɚ 1.12

(ɇɚ ɤɢɧɟɦɚɬɢɤɭ ɦɚɬɟɪɢɚɥɶɧɨɣ ɬɨɱɤɢ)

ɇɟɛɨɥɶɲɨɟ ɬɟɥɨ ɞɜɢɠɟɬɫɹ ɩɨ ɝɥɚɞɤɨɣ ɜɧɭɬɪɟɧɧɟɣ ɩɨɜɟɪɯɧɨɫɬɢ ɩɨɥɨɝɨ ɜɟɪɬɢɤɚɥɶɧɨɝɨ ɰɢɥɢɧɞɪɚ ɪɚɞɢɭɫɚ R. ȼ ɧɚɱɚɥɶɧɵɣ ɦɨɦɟɧɬ ɜɪɟɦɟɧɢ ɫɤɨɪɨɫɬɶ ɬɟɥɚ ɧɚɩɪɚɜɥɟɧɚ ɩɟɪɩɟɧɞɢɤɭɥɹɪɧɨ ɨɫɢ ɰɢɥɢɧɞɪɚ ɢ ɪɚɜɧɚ ȣ0 . Ɉɩɪɟɞɟɥɢɬɶ ɡɚɤɨɧɵ ɢɡɦɟɧɟɧɢɹ ɫɤɨɪɨɫɬɢ ɢ ɭɫɤɨ-

ɪɟɧɢɹ ɦɚɬɟɪɢɚɥɶɧɨɣ ɬɨɱɤɢ ɜ ɰɢɥɢɧɞɪɢɱɟɫɤɨɣ ɫɢɫɬɟɦɟ ɤɨɨɪɞɢɧɚɬ, ɚ ɬɚɤɠɟ ɭɝɨɥ D(t) ɦɟɠɞɭ ɫɤɨɪɨɫɬɶɸ ɢ ɭɫɤɨɪɟɧɢɟɦ.

Ɋɟɲɟɧɢɟ

I. Ȼɭɞɟɦ ɫɱɢɬɚɬɶ ɬɟɥɨ ɦɚɬɟɪɢɚɥɶɧɨɣ ɬɨɱɤɨɣ, ɤɨɬɨɪɚɹ ɞɜɢɠɟɬɫɹ ɩɨ ɰɢɥɢɧɞɪɢɱɟɫɤɨɣ ɩɨɜɟɪɯɧɨɫɬɢ ɫ ɩɨɫɬɨɹɧɧɨɣ ɜɟɪɬɢɤɚɥɶɧɨɣ ɫɨɫɬɚɜɥɹɸɳɟɣ ɭɫɤɨɪɟɧɢɹ, ɪɚɜɧɨɣ ɭɫɤɨɪɟɧɢɸ ɫɜɨɛɨɞɧɨɝɨ ɩɚɞɟɧɢɹ g .

Ⱦɥɹ ɪɟɲɟɧɢɹ ɡɚɞɚɱɢ ɜɵɛɟɪɟɦ ɰɢɥɢɧɞɪɢɱɟɫɤɭɸ ɫɢɫɬɟɦɭ ɤɨɨɪɞɢɧɚɬ, ɨɫɶ Z ɤɨɬɨɪɨɣ ɫɨɜɩɚɞɚɟɬ ɫ ɨɫɶɸ ɰɢɥɢɧɞɪɚ, ɤɚɤ ɩɨɤɚɡɚɧɨ ɧɚ ɪɢɫ. 1.18. ɇɚ ɬɨɦ ɠɟ ɪɢɫɭɧɤɟ ɢɡɨɛɪɚɠɟɧɵ ɨɪɬɵ er, eM ɢ ez ɰɢɥɢɧɞɪɢɱɟɫɤɨɣ ɫɢɫɬɟɦɵ. Ɉɫɶ, ɨɬ ɤɨɬɨɪɨɣ ɨɬɫɱɢɬɵɜɚɟɬɫɹ ɭɝɨɥ M ɫɢɫɬɟɦɵ

ɤɨɨɪɞɢɧɚɬ, ɧɚɩɪɚɜɢɦ ɧɚ ɩɨɥɨɠɟɧɢɟ ɬɟɥɚ ɜ ɧɚɱɚɥɶɧɵɣ ɦɨɦɟɧɬ ɜɪɟɦɟɧɢ.

Z

 

 

 

 

ez

eM

 

O

M

ȣ0

 

 

 

 

g

 

r

 

 

 

X

 

Ɋɢɫ. 1.18

 

 

Ƚɥɚɜɚ 1. Ʉɢɧɟɦɚɬɢɤɚ ɦɚɬɟɪɢɚɥɶɧɨɣ ɬɨɱɤɢ ɢ ɩɪɨɫɬɟɣɲɢɯ ɫɢɫɬɟɦ

39

II. ȼ ɫɨɨɬɜɟɬɫɬɜɢɢ ɫ ɭɫɥɨɜɢɹɦɢ ɡɚɞɚɱɢ ɢ ɜɵɛɪɚɧɧɨɣ ɫɢɫɬɟɦɨɣ ɤɨɨɪɞɢɧɚɬ ɡɚɩɢɲɟɦ ɧɚɱɚɥɶɧɵɟ ɡɧɚɱɟɧɢɹ ɩɪɨɟɤɰɢɣ ɫɤɨɪɨɫɬɢ ɞɥɹ

ɪɚɫɫɦɚɬɪɢɜɚɟɦɨɝɨ ɬɟɥɚ:

 

Xr (0) 0 , XM (0) X0 , Xz (0) 0 .

(1.120)

ȼɨɫɩɨɥɶɡɭɟɦɫɹ ɮɨɪɦɭɥɚɦɢ (1.103) ɢ (1.104) ɞɥɹ ɩɪɨɟɤɰɢɣ ɫɤɨɪɨɫɬɢ ɢ ɭɫɤɨɪɟɧɢɹ ɬɟɥɚ ɧɚ ɧɚɩɪɚɜɥɟɧɢɹ, ɡɚɞɚɜɚɟɦɵɟ ɨɪɬɚɦɢ ɰɢ-

ɥɢɧɞɪɢɱɟɫɤɨɣ ɫɢɫɬɟɦɵ:

 

 

 

 

 

ȣr

 

ȣM

 

ȣz

 

 

 

 

(1.121)

r ,

rM ,

z ,

 

 

 

ar

 

 

2

, aM

 

 

 

 

 

(1.122)

r rM

2rM rM , az

z .

Ʉɪɨɦɟ ɬɨɝɨ, ɜ ɫɨɨɬɜɟɬɫɬɜɢɢ ɫ ɭɫɥɨɜɢɹɦɢ ɡɚɞɚɱɢ, ɡɚɩɢɲɟɦ:

r(t) R ,

aM (t)

0 , az (t)

 

g .

 

(1.123)

III. ɂɫɩɨɥɶɡɭɹ (1.121) – (1.123),

ɩɨɥɭɱɢɦ ɡɚɤɨɧɵ ɢɡɦɟɧɟɧɢɹ

ɩɪɨɟɤɰɢɣ ɫɤɨɪɨɫɬɢ ɢ ɭɫɤɨɪɟɧɢɹ:

 

 

Xr (t)

0 , XM (t)

X0 , Xz (t) gt ;

 

(1.124)

a

 

(t)

 

X2

, a

(t)

0 , a

 

(t) g .

(1.125)

r

0

z

 

 

 

R

M

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Ɍɚɤɢɦ ɨɛɪɚɡɨɦ, ɢɫɤɨɦɵɣ ɡɚɤɨɧ ɢɡɦɟɧɟɧɢɹ ɫɤɨɪɨɫɬɢ ɢ ɭɫɤɨɪɟɧɢɹ ɜ ɰɢɥɢɧɞɪɢɱɟɫɤɨɣ ɫɢɫɬɟɦɟ ɤɨɨɪɞɢɧɚɬ ɢɦɟɟɬ ɫɥɟɞɭɸɳɢɣ ɜɢɞ:

ȣ

X0eM gtez ,

(1.126)

a

 

X2

er gez .

(1.127)

0

 

 

R

 

 

Ɉɩɪɟɞɟɥɢɦ ɬɚɤɠɟ ɢɫɤɨɦɵɣ ɭɝɨɥ D ɦɟɠɞɭ ɫɤɨɪɨɫɬɶɸ ɢ ɭɫɤɨɪɟɧɢɟɦ ɬɟɥɚ:

cosD

ȣ a

 

 

g 2t

 

 

 

 

 

.

(1.128)

Xa

 

 

 

§

 

2

·

2

 

·

 

 

 

 

 

 

 

 

 

 

2

2 ¨

§X0

 

 

2 ¸

 

 

 

 

 

X0

gt

 

¨

 

¸

 

g

 

 

 

 

 

 

¨

¨

R

¸

 

¸

 

 

 

 

 

 

 

©

¹

 

 

 

 

 

 

 

 

 

©

 

 

 

 

 

¹

 

 

1.4. Ɂɚɞɚɱɢ ɞɥɹ ɫɚɦɨɫɬɨɹɬɟɥɶɧɨɝɨ ɪɟɲɟɧɢɹ

Ɂɚɞɚɱɚ 1

ɂɡ ɩɭɲɤɢ, ɧɚɯɨɞɹɳɟɣɫɹ ɧɚ ɫɚɦɨɥɟɬɟ, ɥɟɬɹɳɟɦ ɝɨɪɢɡɨɧɬɚɥɶɧɨ ɫɨ ɫɤɨɪɨɫɬɶɸ Xɫɚɦ , ɜɵɩɭɳɟɧ ɫɧɚɪɹɞ ɜ ɧɚɩɪɚɜɥɟɧɢɢ ɞɜɢɠɟɧɢɹ ɫɚɦɨ-

40

ɆȿɏȺɇɂɄȺ. ɆȿɌɈȾɂɄȺ Ɋȿɒȿɇɂə ɁȺȾȺɑ

ɥɟɬɚ. ɋɤɨɪɨɫɬɶ ɫɧɚɪɹɞɚ ɨɬɧɨɫɢɬɟɥɶɧɨ ɫɚɦɨɥɟɬɚ ɪɚɜɧɚ Xɫɧ . ɉɪɟɧɟɛ-

ɪɟɝɚɹ ɫɨɩɪɨɬɢɜɥɟɧɢɟɦ ɜɨɡɞɭɯɚ, ɧɚɣɬɢ:

1) ɭɪɚɜɧɟɧɢɟ ɬɪɚɟɤɬɨɪɢɢ ɫɧɚɪɹɞɚ ɨɬɧɨɫɢɬɟɥɶɧɨ Ɂɟɦɥɢ y( x) ;

c

 

c

2) ɭɪɚɜɧɟɧɢɟ

ɬɪɚɟɤɬɨɪɢɢ

ɫɧɚɪɹɞɚ

ɨɬɧɨɫɢɬɟɥɶɧɨ

ɫɚɦɨɥɟɬɚ

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

y ( x ) ;

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3) ɭɪɚɜɧɟɧɢɟ

ɬɪɚɟɤɬɨɪɢɢ

ɫɚɦɨɥɟɬɚ

ɨɬɧɨɫɢɬɟɥɶɧɨ

ɫɧɚɪɹɞɚ

cc

 

 

cc

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

y ( x

 

) .

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Ɉɬɜɟɬ: 1)

y

 

 

g

x

2

 

c

 

 

g

c

2

 

 

2 Xɫɚɦ Xɫɧ 2

 

, 2) y

 

2Xɫɧ2

(x )

 

,

 

 

 

cc

 

g

 

cc 2

 

cc

 

 

 

 

 

 

 

 

 

 

 

 

3)

y

 

 

 

2Xɫɧ2

 

(x )

, x

 

0 . Ɉɫɢ X, X' ɢ X'' ɞɟɤɚɪɬɨɜɨɣ ɫɢɫɬɟɦɵ ɤɨɨɪ-

ɞɢɧɚɬ ɧɚɩɪɚɜɥɟɧɵ ɝɨɪɢɡɨɧɬɚɥɶɧɨ ɜɞɨɥɶ ɫɤɨɪɨɫɬɢ ɫɚɦɨɥɟɬɚ, ɚ ɨɫɢ Y, Y' ɢ Y'' – ɜɟɪɬɢɤɚɥɶɧɨ ɜɜɟɪɯ, ɩɪɢ ɷɬɨɦ ɧɚɱɚɥɨ ɤɨɨɪɞɢɧɚɬ ɫɢɫɬɟɦɵ XY ɫɨɜɩɚɞɚɟɬ ɫ ɩɨɥɨɠɟɧɢɟɦ ɫɚɦɨɥɟɬɚ ɜ ɦɨɦɟɧɬ ɜɵɫɬɪɟɥɚ ɩɭɲɤɢ.

Ɂɚɞɚɱɚ 2

Ʌɨɞɤɚ ɩɟɪɟɫɟɤɚɟɬ ɪɟɤɭ ɲɢɪɢɧɨɣ d ɫ ɩɨɫɬɨɹɧɧɨɣ ɨɬɧɨɫɢɬɟɥɶɧɨ ɜɨɞɵ ɫɤɨɪɨɫɬɶɸ ȣ , ɩɟɪɩɟɧɞɢɤɭɥɹɪɧɨɣ ɫɤɨɪɨɫɬɢ ɬɟɱɟɧɢɹ ɪɟɤɢ, ɦɨɞɭɥɶ ɤɨɬɨɪɨɣ ɧɚɪɚɫɬɚɟɬ ɨɬ ɛɟɪɟɝɨɜ ɤ ɫɟɪɟɞɢɧɟ ɪɟɤɢ ɩɨ ɥɢɧɟɣɧɨɦɭ ɡɚɤɨɧɭ, ɦɟɧɹɹɫɶ ɨɬ 0 ɞɨ u. ɇɚɣɬɢ ɬɪɚɟɤɬɨɪɢɸ ɥɨɞɤɢ, ɚ ɬɚɤɠɟ ɫɧɨɫ ɥɨɞɤɢ l ɜɧɢɡ ɩɨ ɬɟɱɟɧɢɸ ɨɬ ɦɟɫɬɚ ɟɟ ɨɬɩɥɵɬɢɹ ɞɨ ɦɟɫɬɚ ɩɪɢɱɚɥɢɜɚɧɢɹ ɧɚ ɩɪɨɬɢɜɨɩɨɥɨɠɧɨɦ ɛɟɪɟɝɭ ɪɟɤɢ.

Ɉɬɜɟɬ:

y

Xd

x , ɩɪɢ y < d/2;

y d

d 2

 

Xd

x , ɩɪɢ y > d/2;

u

2

u

 

 

 

 

 

 

ud

l 2X . Ɉɫɶ X ɞɟɤɚɪɬɨɜɨɣ ɫɢɫɬɟɦɵ ɤɨɨɪɞɢɧɚɬ XY ɧɚɩɪɚɜɥɟɧɚ ɜɞɨɥɶ

ɛɟɪɟɝɚ ɪɟɤɢ, ɚ ɨɫɶ Y – ɩɨɩɟɪɟɤ ɪɟɤɢ. ɇɚɱɚɥɨ ɫɢɫɬɟɦɵ ɤɨɨɪɞɢɧɚɬ, ɠɟɫɬɤɨ ɫɜɹɡɚɧɧɨɣ ɫ ɛɟɪɟɝɨɦ ɪɟɤɢ, ɫɨɜɩɚɞɚɟɬ ɫ ɦɟɫɬɨɦ ɨɬɩɥɵɬɢɹ ɥɨɞɤɢ.

Ɂɚɞɚɱɚ 3

ɉɨ ɞɜɢɠɭɳɟɦɭɫɹ ɜɧɢɡ ɷɫɤɚɥɚɬɨɪɭ ɫɩɭɫɤɚɟɬɫɹ ɩɚɫɫɚɠɢɪ ɫɨ ɫɤɨɪɨɫɬɶɸ X ɨɬɧɨɫɢɬɟɥɶɧɨ ɷɫɤɚɥɚɬɨɪɚ. ɋɤɨɪɨɫɬɶ ɷɫɤɚɥɚɬɨɪɚ ɪɚɜɧɚ u. ɋɩɭɫɤɚɹɫɶ ɩɨ ɧɟɩɨɞɜɢɠɧɨɦɭ ɷɫɤɚɥɚɬɨɪɭ ɩɚɫɫɚɠɢɪ ɩɪɨɯɨɞɢɬ N ɫɬɭɩɟɧɟɣ. ɋɤɨɥɶɤɨ ɫɬɭɩɟɧɟɣ N' ɩɪɨɣɞɟɬ ɩɚɫɫɚɠɢɪ, ɫɩɭɫɤɚɹɫɶ ɩɨ ɞɜɢɠɭɳɟɦɭɫɹ ɷɫɤɚɥɚɬɨɪɭ?