. Ndu BN =CM thi frBC-'NC b-
vI do d6 trong h0 toa dd Ox, phuong trinh
chuydn d6ng cira vAt ld
(Ln -\
x=x'-/n=2,5 + 5sinl ( *t- 3 6)_ l(cm)
o Ndu lfc ddu vAt chuydn d6ng theo chidu Am thi lap luAn vI tinh to6n tuong tu nhu tr€n ta tim
( t- {-\
duoc: x=-2,5 + 5sinl (3 -::t+? 6)'I (cm)
NhAn x6t. Ban Ddu Ngqc Huy,l2A, THPT Anh Sdn
1, Nghe An c6 ltri gi6i t&. C6c ban khiic c6 ldi giAi
dfng l]:
Vinh Phtic : NguydnThi PhLrong Dung, l2A3,T\7PT
chuy6n Vinh Phric ; Bdc Giangz Daong Trung Hi€it, 128, THPT NK Ngo Si Lien ; Ngh6 Anz Hodng Vdn Dtrong, A3K3l, Nguydn Duy Ctong. 12A3. NguyinVdn Hda, A3K3l, TI{PT chuyon Phan BQi Chau, Vinh ; Ti€n
Giang: Nguy€n Vinh Phric, l2Al8, TIIPT chg Gao ;
Phri Ydn: L€ CungTtirrtg, IzC2,TItrIILE H6ng Phong,
Tuy Hba ; Quing Ngii: Le Hit Kiet,l2A2, TIIPT Drlc Phd I ; Binh Dinh : Nguydn Hiiu Nhdn, 12L, THPT chuy6n Lc Quy D6n ; Bdc Ninh : Cftu Ti€'n Anh, l2Al,
TFIPT Y€n Phong I.
MAIANH
BiiL2l328.Ti.ln sd clti ct?a cic ompt kc ,,\1,
A:, As lrong sd do ci lririt dti'i, kltiriitir ,'1 r'r) IJ
vt)o ntit n.q,udrr diin cd ltiiu dien 11,6'11 = .1,.t\'
Bi1t t'itttg tliin n'ci cLio cdc antpe ki'rti't trltri stt
t'(t'i ctic tliin trrt trong ntttclL, vt) R = 3 (kO) ;
Rt = I (kO)' R: = 2 (kO), Rt = I (kQ).
Ldi giii. Vi diOn tr& cira ciic ampe kd rAt nh6 nOn c5 thd chap cilc didm mii ampe kd thhnh
didm chung C. Tir d5 :
Rnc = 1 (kO) ; Rru = 1' |ftO) vI Rn, = 11 7 1reilDdng dien mach chinh lit: L*=L=2,1(mA) Ddng dien mach chinh lit: L*=L=2,1(mA)
RAB
vd Un = 2,1(Y); (lr, = 1,21y). Dbng dien qua
m6i di6n trd R 11 1,,= 0,7(mA) vh qua R1, R2, R3 tudng fillg 1)r 11 = 1;2(mA) i /z = 0,6(mA)vh 1. =
0,3(mA). Can ctl vdo chi6u vI cudng d6 ddng
di6n qua cdc diOn trd suy ra chi6u ddng di6n vh cudng do dbng diOn qua cilc ampe kc. Tt d6 tim duo. c sd chi ctra c6c ampe kd Ar, A, vh A., tuong ung bang 0,1(mA) ; 0,2(mA) vd 0,3(mA).
NhAn x6t. C6c ban c6ldi giii vh ddp sd dring :
Bdc Giang ; DrrtngTrung HiA'u, 11B, THPT NK NgO
Si Li6n ; Vinh Phric : Nguydn Dr?c Trong, 10A3, Nguy,in Thi Phuong Dung, 12A3, TIIPT chuyen \tnh
Phric; NghQ An z Nguydn Vdn Hda, A3K31, THPT chuydn Phan BOi Chdu, Vinh ; Quing Nam: Ngrrydr
Vdn Hi€u, 1212, TLtrT chuy6n Nguy6n Binh Khiem ; '
Bdc Ninh: ChuTi€h Anh, l2Al, THPT Ycn Phong I I
Hlr TAy: L€ Hodn,12A1, TIIPT Ddng Quan.
MAI ANH