Файл: ГДЗ. Физика 9кл_Перышкин_Гутник_2001.pdf

17. o = o0

+ sx

JZg__ [ueh ^hdZaZgh qlh ijb jZ\ghmkdhj_gghf

^\b`_gbb k mkdhj_gb_f Zo b gZqZevghc kdhjhklvx v0x i_j_f_s_gb_

jZ\gh sx = v0xt +

ax t

ihwlhfm o = o0+ v0xt +

ax t

.

18.

2

2

>Zgh

J_r_gb_

ax

f k2

vx(t) = v0x + axt = 0,1t \ f k2).

v0x = 0

ax t 2

0,1 t 2

2

x0 = 0

x(t) = x0 + v0xt +

=

= 0,05t .

2

2

GZclb vx(t), x(t).

Hl\_l v0x

f k

19.

>Zgh

J_r_gb_

|v\_ df q

|vf| = ||v\| – |v\||

v\ ↑↑ vf

|vf| = ||v\| + |v\||

Z |vhlg| = 0

ijb v\ ↑↓ vf.

[ |vhlg_ df q

Z) v\

↑↑ vf b v\ ↑↓ vf |vf| = |40 df/q ± 0 df/q| =

\ |vhlg_ df q

= 40 df/q.

] |vhlg_

df q

[) v\ ↑↑ vf |vf| = |40 df/q – 10 df/q| = 30 df/q.

v\ ↑↓ vf

|vf| = |40 df/q + 10 df/q| = 50 df/q.

\ v\

↑↑ vf |vf_

_ df q ±df q_

v\ ↑↓ vf

|vf_ _ df q df q_ df q

] v\

↑↑ vf |vf_

_ df q df q_ df q

v\ ↑↓ vf

|vf_ _ df q ±df q_ df q

GZclb vf.

beb df q [ df q beb df q

20. Kdhjhklv dZl_jZ hlghkbl_evgh [_j_]Z ih l_q_gbx d =

=

+

= 6vl a^_kv vd ²kdhjhklv dZl_jZ hlghkbl_evgh \h^u vl —

kdhjhklv l_q_gby \h^u hlghkbl_evgh [_j_]Z kdhjhklv dZl_jZ

hlghkbl_evgh [_j_]Z ijhlb\ l_q_gby

vd = vd

– vl = 4vl LZdbf

h[jZahf

v +

=

6

= 1,5.

v −

4

21.

ρ =

m

=

3,87 10−3

3

V

3 10−3 3

d] f

Fu \b^bf qlh iehlghklv

v0

= 0

L d

v1 =

v2 jZ\ghmkdhj_ggh_ ^\b`_gb_ lh

t

k

p1 =

p2 = p

d] f k2 1 c d] f k

t = 1c

p d] f k

GZclb v.

Hl\_l p1

=

p2 =

29.

L d m ² ihklhyggZy \_ebqbgZ lh baf g_gb_ bfimevkZ [m^_l

hij_^_eylvky lhevdh baf_g_gb_f kdhjhklb Ih ]jZnbdm kf aZ^Zqm

\b^gh qlh _keb

t1 =

t2 lh b

v1 =

v2 b agZqbl

p1

=

p2.

30.

< mkeh\byo k\h[h^gh]h iZ^_gby

kdhjhklb h[hbo

rZjbdh\ \

ex[hc fhf_gl \j_f_gb [m^ml h^bgZdh\u b ke_^h\Zl_evgh

hlghr_gb_ bo bfimevkh\ [m^_l aZ\bk_lv ebrv hl hlghr_gby bo

fZkk LZd dZd ih mkeh\bx h[t_fu h^bgZdh\u hgh [m^_l jZ\gh

ρ

=

8,9 103

3

≈ 3,3.

hlghr_gbx iehlghkl_c f_^b b Zexfbgby

ρ

2,7 103

3

BlZd \ ex[hc fhf_gl

\j_f_gb f_^guc rZjbd bf

l bfimevk

ijbf_jgh \ jZaZ [hevr_ q_f Zexfbgb_\uc

31.

1

2

X

1

2

X

>Zgh

J_r_gb_

v1x

f k

+ mv

= mv′

+ mv′

v′

= v

+ v

− v′

):

v2x

f k

mv

2 x

2 x

=

v1′x

1x

1x

2 x

2x

1x

1x

f k

f k f k ±f k

f k

GZclb v.

Hl\_l v′

f k

2x

32.

1

2

X

33.

(v

); E′ =

(v′2

+ v′2 );

mv

2

mv

2

m

2

2

mv′

2

mv′2

m

E =

1x

+

2 x

=

+ v

1x

+

2x

=

2x

2

2

2

1x

2

2

2

1x

2x

v2

+ v2

f k 2

+ ±f k 2 = 0,05 f2 k2; v′2

+ v′2

±f k 2 +

1x

2 x

1x

2 x

+ f k 2 = 0,05 f2 k2 v2

+ v2

= v′2

+ v′2 E = E′.

1x

2 x

1x

2 x

1

1

34.

k b ν

=

=

Ih ]jZnbdm hij_^_ey_f qlh L

T

2

=p

Ex[Zy ^jm]Zy lhqdZ baf_gy_l kdhjhklv k lhc `_ kZfhc qZklhlhc

35.

<havf_f aZ t

fhf_gl dh]^Z hldehg_gb_ kj_^g_c lhqdb

36.

GZ^h

^\Z h^bgZdh\uo dZf_jlhgZ jZkiheh`blv gZ g_dhlhjhf

jZkklhygbb ^jm] hl ^jm]Z lZd qlh[u bo j_ahgZlhjgu_ ysbdb [ueb

h[jZs_gu ^jm] d ^jm]m ?keb l_i_jv m^Zjblv ih h^ghfm ba gbo b

q_j_a g_dhlhjh_ \j_fy aZ]emrblv ijbdhkgm\rbkv jmdhc d g_fm lh

fu mkeurbf a\md hl \lhjh]h dZf_jlhgZ < hkgh\_ ^Zggh]h hiulZ

e_`bl y\e_gb_ a\mdh\h]h j_ahgZgkZ

37.

Ihevamykv ]jZnbdhf hij_^_ey_f

Z

ijb =p

Zfieblm^Z

mklZgh\b\rboky dhe_[Zgbc [m^_l [hevr_ q_f ijb =p [ qlh[u

Zfieblm^Z mklZgh\b\rboky dhe_[Zgbc [ueZ fZdkbfZevghc dZq_eb

gZ^h ih^lZedb\Zlv k qZklhlhc =p \ kh[kl\_ggZy qZklhlZ dZq_e_c

jZ\gZ qZklhl_ \ugm`^Zxs_c kbeu l _ =p

38.

>Zgh:

J_r_gb_

l

kf

f

Fl = Ff; mg = BIl I = mg = 0,002

9,8

2

m

]

d]

=

B = 4 10

-2

Bl

4 10−2

0,1

Le

= 4,9 A.

GZclb I.

Hl\_l: I = 4,9 A.

39.

< ^Zgghf kemqZ_ jhev p_gljhklj_fbl_evghc kbeu \uihegy_l

kbeZ k dhlhjhc fZ]gblgh_ ihe_ ^_ckl\m_l ^\b`msbcky we_dljhg

Ihevamykv ijZ\behf e_\hc jmdb hij_^_ey_f qlh we_dljhg \e_l_e \

dZf_jm \ lhqd_ <.