Vat li HDC

Gqi t ld thli gian tir hic 7h sSng t6i hic hai ngudi g{p nhau.

;{ '-;

TRTIOT\G THpr cHUyEN xnAo sAr cnAr LUQNG vAo LOP 10

ruON vAr li

(Haong ddn chtim gi* ro 5 trang) Ngdy thi: 15 thdng 5 ndm 2016

Thdi gian ldm bdi: 150 Philt

Ciu u 1: (1,5 1: (1 tli6m

a)

(1 d)

vl = lzknlh vz= 4kmlh

Gi6 su hai ngudi gdp nhau tai C nhu hinh vE.

Gqi t ld thli gian tir hic 7h sSng t6i hic hai ngudi g{p nhau

T6i luc g4p nhau thi ngudi di xe dpp vd ngudi di b0 dA di dugc dopn ducrng tucrng img ld:

t, = o_r^= ,,.,

(, )

Sz= BC =rz.t

0,25

Ta c6: sr - sz -l\km (2)

K6t lupn: Hai ngudi gap nhu, lir" 8 gid 15 phrt 0,,25

a)

(0,5 d)

+ Tru6c khi hai ngudi gEP

nhau:

d -10 -8r;(r <1,25h)

* Sau khi hai ngudi g{P nhau:

d - -10 + 8r;(r >1,25h)

HS chi vd itwqc mQt TH cho 0,25 tt

0'5

CAr2z(2dlem

0,25

oo25

1)

0,5d

C6 ba luc tdc duns 16n kh6i eS rhu hinh v6 Ei6u ki6n c6n bdn

P = Fo + F, (YE dring hinh)

Bi6n d6i dugc:

tr

d, = 4 * dn =30.000N/m3

oa' d

0Js.I

+ KhOi g5 Aicn chuy6n do4n ! = xo + @ - h) =l3t* oo25

2.b

1,25d

@ dAu k6o cho d6n hic m6t trdn cua kh6i 96 chpm m{t nu6c C6ng thuc hiQn trong giai dopn ndy 1d

@{t tr6n cua kh6i g5 ti0p xirc v6i mflt nu6c cho d6n luc kh6i g5 vira ra kh6i m{t nu6c

Lpc k6o tdng d6ntt ,F - Fo =201/ <l6n F = P = dc.V =30tr/ 0,25

D6 dich cua kh6i g6 trong giai doan ndy ldr: s : a h - !!!q 0,25

C6ng ctra lgc k6o:

CAu3: tIi6m

a)

1d

t

b)

1d

m, 2009,\ = 600 C

mz = 200 g ,tz :300 C

Ggi mo: 50g nu6c h kh6i lugng nu6c dugc mirc tir binh ndy d6 sang

binh kia

+ Lin l:

* D6 tt binh I sang binh II, ggi nhiQt dQ c0n bing cria binh ll\d tn

Phucrng trinh c6n bSng nhiet: moc(tr, - tr) + mrc(tr, - tr) = 0 0,25

Gi6i pt dugc: /r, -motr* mrt, =360 C

, goi nhiQt dQ cdn blng cira binh I lir r,,

Phucrng trinh cAn bing nhiet:

moc (tr, - br) * (*, - mo) c (tr, - /, ) = o 0r25

Gi6i pt ta tim dugc:

, -motr, * (m, - mo)t,

- 540 c

tll

-m1

0,25 nhu Y a) thi sau cing nhiQt d0

cua hai binh nu6c bing nhau tr, = tr, = t" 015

0,25

- Sau khi thr,rc hiQn nhi6u 16n d6, vO phucrng,diQn trao doi nhiCt bdt toan

tucrng duong v6i viQc tr6n nu6c o hai binh v6i nhau, nhiet dQ c6n bbng

A \ - r\ ,

cuol cung se Ia rc

Phucrng trinh c6n bing nhiQt:

m,c(t,- r, ) + mrc(t"- /, ) = o

Gi6i pt ta duoc: /" = mrtr l- mrt, =450C

mr*m,

0,25

c)

1d

Lt, = t,, - t r, =lml {r, - r, )

Sau lAn dO thri hai, dQ ch6nh lech nhigt d6 cria hai binh 1d:

Lt, = t,, - t,, =lffiA],,,, - t,,) =1ffiA1",

r6ng quin: Lt, =

l;ffir; ).o, "_,

a

J

: -.L,t

-nt

KL: Vay ph6i d6 di dO lqiT 1^6,n.

bin

e

\) zi6

Khai tri6n: Ltn =

Thu c6c

- ,r; = :0.(

a n: lr2r3, 6

rl

il

,4,5, Ta thu du

u cua n: ,4r5rO La ugc

Ltn 190 c 1o,goc 6,490 C 3,990 c 2330 C \40 C 0,940 c

0,25

0,5 4: 2 tli6m

u

* Khi K d6ng:

Ir=1,

Tinh r:lugc: \t = 6f);R,r, = 10Q

Ur=Urrr= Io'&=30V ) I.=+E-=3A , R,,,

0,25

*KhiKm0

VE lai mach +

I1

0,25

Tinh dugc:

&s = 40O

R, IJJ - 40 0

I I

0r25

U, = U r, = U tts= 1.R,r, rrf =YV)

a

a)

0,75d

0,25

0,25

Tr", gm 5c cdntai J ) I = 3oo

VQy phii d[t mdn hirng 6nh hqp v6i tryc chinh g6c 300

Chu y: +Ni5u thitiu dcrn vi trong c5c k6t qui thi trir 0,25-di6m cho tolrn bdi'

+ NOu hqc sinh c6 c5ch giai1.1tar'mir dring thi vdn cho di6m t6i da'