n6n:=const ha yT =aVz vlialdhings6

: (BT, BX ) (CY, CX) (mod zr)

o,c' LW, odB' LVX, OdC' LrZ.

f6t hqp v6i (1), chri f ring A, B, C, D cing

thuQc mQt dunng trdn, ta c6

(o,B"qc)-(o,B"qc):(w,w0-(w,tx)Qrrdrn)

: (BT, BX) - (CY, CX) (mod zr)

: (BD, BA) - (CD,CA) (mod zr) : 0 (mod n) .

Do d6 O,thtdc duong trdn(O"E'C').

Tucrng W Oo, O"theo tht t.u thudc c6c ducrng

trdn (O aC' A' ), (O dA' B' ).

YQy chc bO b6n di6m (B', C', Oa, Oo);

(C', A', Oa, Oo); (A', B', Oa, O") cing thu6c

mQt ducrng trdn vd c6c dudng tron d6 theo thri

t.u c6 tam ld or oz, ot

ld s6 nguy6n tu khi. Do tAn s0 va cham cria

nguy6n tu khi v6i dhy binh ld htr6ng d6i

" JT .r

n6n:=const. hay T =aVz vlialdhings6.V V

Theo phucrng trinh tr1tgthdi cira khi lf tu&ng pV=RT>p=aRV. M[t kh6c dT:2aVdV nen dQ = or.!d!. * Cy .dT

2aV

suyra - C =dQ:4* dT 2 C, =!+1n=zR.22

Vpy nhi6t dung cira khi h C:2R.A

FNhfn x6t. Th6i Nguy6n: Phqm Thanh Binh, 11A1,

THPT chuy6n Th6i Nguy6n; NghQ An: Chu Minh

Th6ng, A3K41, THPT chuy6n Phan B6i Chdu; Dik

Lilk Nguydn Vi€t Sang,lO Li, TIIPT chuy6n Nguy6n Du.

NGUYENXUAN QUANG

*Bdi L2t43t. M6t vdt chiu tdc dQng ding

thdi cila hai lryc F, ,d I tthang aai cO aO

l6n b.dng nhau F1 : Fz : 0,4N.vd dang

chuy€n ddng trdn ddu vcti vdn t6c dO ddi (adsbygoogle = window.adsbygoogle || []).push({});

vo:2rn/s, ban klnh qui dqo R : 1m. NOu tqi

m6t thdi di€m ndo dd ta ngimg tdc dung lu'c

F, thi sau thdi di€m dd 4svdt co t6c d0 bdns

bao nhiAu? Bi€t v4t co kh6i ltrqng m: O,l kg.

Ldi gidi. Do vQt chuy6n rl6ng trdn d6u nOn

vAt chiu tiic dgng cira hqp l1rc hu6ng vio tim

qu! d4o vd c6 dQ lon F' = *Y-' = 0,4 (N).

rheo dAu bdi l4l:l4l =14=f|,P,):t2oo;

(i,h = 6oo, (Fr,h= 6oo.

Chgn hQ truc top dQ

Oxy c6 g}c O ld vi tri

cria vft hic ngring t5c

dpng luc Fr, tryc Ox theo chi6u is,tryc

Oy theo hu6ng cita

hqp luc F6rinn vc).T4i thoi tli6m r:0 H T4i thoi tli6m r:0 H

hic ngring t6c dung (4)

Tt (1) vd (2) suy ra VZ LC'Od,qQ LC'Oa;

vx LB'od,oroz LB,oa.Do d6 VZ llOtOz;VX llqq. Do d6 VZ llOtOz;VX llqq.

Tt (2), (3) vd (4) suy ra NZLO;Oa,

O'02 IO6Oa;NX LO,Od,O'03 LO"Od.

Do d6 NZ llO'O2,NX llO'03. Tu (2) c6

(oror,Qoz) : (vz,vx) : (NZ, NX)

: (O'Oz,O' 03)(moda).

Do d6 O' thuQc duong fidn cO einn (Op2q).A

)Nhfn x6t. Bii to6n ndy kh6, Tod so4n chi nhdn duoc

lcri gi6i cria bpn Nguydn Trung Hi€u, llTl, THPT

chuy€n Hung YGn.

Kh6ng cin gi6 thi6t A, B, C, D cirng thudc mQt iluong ffon, cdc du<rng (O,). (O), (O"), (O7) v61 ctrng di qua

m6t di€m (xem bii T121404, TH&TT 36 404, th6ng2 (adsbygoogle = window.adsbygoogle || []).push({});

nrm 2ol1)'

NGU'EN MINH HA

*Bni Lll43l. Ducti pit t6ng trong m6t xi

lanh co mot mol khi.hAh. Ngadi m d& nong chqm khi, khi dd th€ t{ch cila khi tdng nhrng

tdn so va cham ctia cac nguy€n t* vdo ddy binh kh6ng aAi. fim nhiQt dung cua khf trong qud trinh d6.

Ldi gidi. TAn s6 va ch4m cria ciic nguy€n tu

v6i tl6y binh phU thu6c vdo vfn t5c trung

binh v cua cic nguy6n tu vd mflt ilQ nguy6n

tukhir.Md v=Ji , cdnn = l, N trong d6 try'

N6n:=const ha yT =aVz vlialdhings6

: (BT, BX ) (CY, CX) (mod zr)

n6n:=const ha yT =aVz vlialdhings6

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