#, doc theo mpt phdng nghi6ng.[r]
Trang 1so crAo DUC & EAO T4O QUANG TRI
TRrroNG THPT crilrytN r,0 guf oON of rnr cHeN Der ruynN ogrHr Hec srNH cror
t Gp tz cAp riNn NAvr Hoc 2ots-zozo
Mdn thi: VAT LY
Thdi gian ldm bdi: I B0 philt (Da thi g6m c6 02trang)
m
Cflu I (3,0 di€m) .
Ttr chdn cira mQt c6i n6m ttrOi luqng M, truydn cho m6t vQt nh6
khOi tuqng m vQn tO #, doc theo mpt phdng nghi6ng HQ s6 ma s6t
giira vft vd n6m ld p, goc gita m4t ph5ng nghi6ng clra ndm vd m6t
ph[ng ngang li o, n6m c6 dQ cao h 86 qua ma s6t gifia n6m vd m{t
phdng ngang Tim v4n t6c vo cgc d4i dO vflt kh6ng vuot qua dinh
cira mdt ph6ng nghi6ng
Hufng din ch6m
h
Ciu II (4,0 di€m) .
Edt mach diQn c6 so do nhu hinh bon vdo mOt hiOu diQn th6 kh6ng aoi u.
Hai ddn gi6ng nhau vd diQn tro khong thay d6i Khi di6u chinh bi6n tro R6 ta
th6y v6i hai gi|trl Rur : 1Q vi Rbz :4Q thi c6ng su6t ctra bitin tr6 c6 ctng m6t
gi|tri P:25W Edn D1 c6 c6ng su6t pr :125W.
a) Tinh hiQu diQn th.5 U, diQn tro R vd diQn trd m6i ddn?
b) Tim gi|tri Rb de c6ng su6t tiOu thp tr6n bi6n tr6 d4t gi6tri cpc d4i Tinh
gi6 tri cgc d4i d6
Huttug d6n ch6m
U
D6 vat khdng vugt qua ducv c <tinh thi khi vomax vat dung lai t4i rlinh n€m tric ld ctng
vfln t6c v vdi n6m.
0,5
Ddng lugng theo phuong ngang dugc b6o todn:
myom*cosd =(m+ M)v
mcosa 1' v=
m+M vorru,
1 0
Ap dpng itlnh lu6t b6o todn nlng lugng:
* z *uo,n ' = *(* z' + M)v2 + mgh + pmg cos
aT-stna
1,0
2(m+ M gh l+ pcota
1V^
utnax
M +msin2 a
0 5
Trang 1/5
Trang 2Ciu NQi dung Ei6m
a) Ap dung ngu6n tuong ducrng cho hai nhSnh (U, R) vd Dz
RR^
5
R+R, R,,
U ,R+R,
0,5
/z\2
I 5 ln,
In,+r] n
C6ng su6t bi€ntr6: P =
<> Rr'+ (,,
y2 5
Ro+12 =0
P
0,5
Tt he thfc Vi-61, ta c6:
RorRo, = 12
R^ + Ru, =t-r, ={
, =z(a)
€:rs(v)
0,5
.I -l U 25(rr)
/3(o) (o)
R=10
RD 5
1,0
a) Truong hqp d: l,5cm, tim b6n kinh qu! dpo vd thdi gian chuy6n dQng cta electron trong tir trucrng
b) Tim d nh6 ntr6t AO thdi gian electron chuy6n d6ng trong tu trucrng la lcrn ntr6t tim thcyi
gian d6
Hu6,ng din chdm
I
V
"4
0
-+
B
@
d
Trang2/5
Ir I 1 I
l.-ft R,., I
1t tr u "lI
Tri phuong trinh c6ng su6t bi6n trd tr6n, 6p dpng bdt dtngthric C6si ta c6:
r2
P*^=L:28,725(W) khi & =r:2(A)
CAu III (4,0 di€m) "
M6t electron dang chuy6n dQng voi vfn 6c vo: 8.107m/s thi bay vdo
mQt virng c6 tir trudng d0u bO aay d, t o lu6n vu6ng goc vcri cim ring tu i
vdi B : 3.10-2 T Khi vdo tt trudng, io hqp v6i ph6p tuy6n m{t gi6i h4n
cria tr) trudng mQt g6c o - 300 nhu hinh v6 86 qua t6c dung ctra trgng
truong Cho diQn tich vd kh6i luqng cta electron ld q : -1,6.10-reC vir m.
:9,0.10-3lkg.
Trang 3a) B6n kinh qu! tl4o R dugc x6c cllnh
2
lo,luon=ry
e.R -
#=t,S(cm)
1 0
d : R
= qu! clpo trong tt'trudng ld mOt cung trdn c6 g6c P: nl3 0,5
Thdi gian chuy6n tlQng cria electron trong tt trudng ld:
t = 0R
=1,875r.10-10 ^r 5,89.10-'o (r)
yo
1,0
b) D6 d,,,1, thi qu! dpo ti6p xirc v6i bd b6n kia Qu! clpo trong tu trucrng ld mQt cung trdn
c6g6c y:4n13.
0, 5
* d*io= R + R sin a = 2,25(cm)
t,,* =f R =2,5n.10-to x7,85.10-'o (s)
yo
1 ) 0
C0u IV (3,0 diAm) .
MQt qui cAu trong sut5t c6 chi6t su6t n d{t trong kh6ng khi MOt tia s6ng dugc chi6u vdo qui
cAu du6i g6c t6i i (i < 905.
a) Hdy chimg minh tia sSng lu6n 16 ra kh6i qui cAu sau hai lAn khric x4
b) Tim bi6u thrlc g6c lQch cira tia sdng sau khi truyOn qua qui cAu Ap dUng s6 i : 600,
t;
n=1J.
Hutitrg dfin chdm
a) Trong mQt mit phing t6ib6tky thi6t diQn cta mflt
phlng t6'i vd qu6 cAu h mQt hinh trdn d lan khirc xa thri nh6t, ta c6:
J
Slnf=-<-=Sln
+ r lirn Vfly khi tia s6ng d6n mflt cAu lAn thir hai n6 sE khric
xp ra m6i trucvng b6n ngodi
2,0 (h.vE
0,5)
b) Tri hinh v6, ta c6:
sin I
, - arcsln
-n
o=2(i-r)=2
1,0
Trang 4dung
600 sin 600 600
-arcsmlS-CiuV (6,0 didm) .
a) MOt ld xo c6 dQ ctmg 20N/m, dAu tr6n duoc treo vdo m6t diom c6 dinh, dAu du6i g6n v{t
nh6 A cO khOi luqng 1009 Khi vQt A dang nim y6n o vi trf c6n bang thi mQt vQt e kh6ituqng
2009 chuyOn dQng tir du6i l6n v6i v{n t6c 37,5J6 cm/s va cham mdm vdo vQt A Tim bi6n dQ
dao dQng cta hQ v{t sau d6
b) Hai con l6c dcrn gi6ng hQt nhau md c6c vQt nh6 c6 khdi lugng m: 100g vd mang diQn tich ducrng q nhu nhau, ducvc treo o mQt noi tr6n mi4t ddt Trong m6i vung kh6ng gian chuam6i con l6c c6 mQt diQn trudrng dAu Hai diQn trucrng ndy c6 ctng cu&ng dO t: 10'V; rrhung c6c dulng sric nguoc hu&ng nhau Bitit phucrng cria c6c dudng sric hgp vdi phucrng thang dring mQt g6c o:
9.oo,tiu ti5c trgng trudng B: 10m/s2 vd chu ky daotQng di6u hda cria c6c con l6c gap rrrrl 1,236 lan llm q
c) Hai ch6t di6m dao dQng di6u hda doc theo ducmg thing o1O2 ctng tAn s6 cung bi6n dQ
'q = +Ji km)nhmglQch pha nhau2nl3.gi6t or vd oz chinh ld vi tri
c6n bang cira hai ch6t dicm
vd OrOz: 15cm X6c dinh khoang c6ch cr,rc dpi vd cuc ti6u giffa hai ch6t diom do
Hurfng d6n chdm
Theo dinh luat beo todn d6ng lugng:
ffiavn =(*o*mu)v
<+ v - *!I:v, =25J6(cm I s)
mA+ mB
0,5
EQ l6n li dQ ctra hQ vft ngay sau khi va cham ld:
lr'l = do,- Lto =@*P -ry =rckm)
0,5 a)
Bi6n d0 dao tl6ng cria h0 v6t:
k
x'2 +(mn+m, ),'
1,0
b) Lpc cliQn t5c dpng l6n diQn tfch F: qE
Trgng luc bi6u kiiSn t6c dpng l6n mdi con l6c ld:
P2 + F2 -2pF cosa = P2+F2_PF
P2 + F2 +2PFcosa = P2+F2+PF
P1 =
Pr=
0,5
Trang415
Trang 5Md theo adru, L= E = E =L236
r, !g, \p,
05
r = 0,5(N)
F =2(N)
g = 0,5.10-t (C)
q =2.10-' (c)
1,0
c) Gi& sir phuong trinh dao dQng cria hai ch6t di6m ld:
xt = 4'Ecos(att)(cm);xz =
'l-3cos(att +2t lz)(cm) Khoang c6ch gifia hai chAt di6m d thoi di6m t ld:
4 =loro, * xz -r, I = |t5 +t2cos(att - r I 6)l(cm)
1,0
d =27cm
d*r, =3cm
1,0
Trang 515