bai tap nang cao ly 10

Phan hai mJCR^G M^A!^ GlAl VA DAP s6 DONG HOC CHnt DI€M 1.1 Sit dung edng thfic tfto v t o td'e trung binh : y ^ ^2 - ^1 ^ Ax * t2 - tj At a) Ax = 2,3 m ; At = 1,0 s ; v = 2,3 m/s b) Ax = 57,5 - 9,2 = 48,3 m ; At = s ; v = 16,1 m/s e) A X = 57,5 m ; At = 5,0 s ; Vji, = 11,5 m/s 1.2 Chgn true Ox trung vdi dutog chay va cd gd'c la dilm xudt phat cua ngudi Vi chuyin ddng theo mdt chilu ndn dd ddi trung vdd qutog dutog chay cua ngudd dd a) Qutog dutog chay ddu la : 51 = 5.(4.60) = 1200 m Qutog dutog chay sau la : 52 = 4.(3.60) = 720 m Qutog dutog ngudd dd chay duge la : S = Sl + S2 = 1200 + 720 = 1920 m =1,920 km b) Vi chuyin ddng chi theo mdt chilu ndn ca thcd gian chay vdn tic trung bito btog tdc dd trung bito va bdng : s 1920 , ^^ , ^'^'=1=7:60=^'^^'"/^ Chd y : Khdng ldy trung binh hai vto tdc vi thod gian chay khac toau 90 1.3 Chgn true Ox trtog vdd ehilu dgc cua bl boi, gd'c O la dilm xudt phat a) Ax = 50 m ; At = 40 s ; Vji, = — = 1,25 m/s ; As = 50 m ; tde dd trung bito = -;— = -TTT = 1,25 m/s At 40 b) Ax = - 50 m ; At = 42 s ; Vtb = = - 1,19 m/s ; As = 50 m ; tdc dd trung bito = -r— = -rr- =1,19 m/s ^ At 42 c) Ax = 0, Vtb = ; As = 50 + 50 = 100 m ; 100 At = 40 + 42 = 82 s ; td'e dd trung bito = —— « 1,22 m/s 82 1.4 1,5 2,0 2,5 3,0 3,5 4,0 t(h) Hinh 1.1 G Theo dd thi, hai xe dudi kip toau sau h 30 min, tai vi tri each Ha Ndi 210 km Chii y : Cd thi giai bang tfto todn tou sau : Xe thfi hai dtog lai d vi tri.each Ha Ndi la 70.1,5 = 105 km Khi xe bat ddu chang tilp theo thi xe thfi todt d vi tri each Ha Ndi 60.2 =120 km Phuong trinh chuyin ddng cua hai xe kl tfi lue dd la : 91 Xl = 120 + 60t X2 = 105 + 70t Xe thfi hai dudi kip xe thfi nhdt Xi = X2 Tfi hai phuong tnnh trdn ta tim dugc t = h 30 va x = Xi = X2 = 210 km Vdy thod dilm dudi kip toau kl tfi lfic xudt phat tai Ha Ndi la h + h 30 = h 30 min, vi tri lfic dudi kip toau each Ha Ndi la 210 km 1.5 a) Phuang trito chuyin ddng cua ngudd di bd va cua ngfidi di xe dap Ito lugt la: Xl = 20 + 5t (1) (2) b) Tfi dd thi ta thdy hai ngudd gap toau sau t = h va tai vi tri x = 40 km e) Giai hai phuong trinh (1) va (2), ta dugc kd't qua t = h va x = 40 km,' dung tou cau b 1.6 a) Cach giai tuong ttt bai tap 1.4 Dd thi cho trdn Hito 1.2G, dilm gd'c tuong tog vdd luc h b) Nhin trdn dd thi ta thdy d td va tau gap t = h 50 ; x = 120 km; tfic la chung gap luc h 50 min, cdch Thato phd Hd Chf Minh 120 km, c) Xl = 30 + 45t X9 = lOt X2 = 60t dd t la thdi gian kl tfi lue d td bat ddu chay X (km) 92 1.7 a) Chgn true Ox cd gdc tai Ha Ndi, chilu hutog vl phfa Hai Phdng Phuong trmh chuyin ddng cua hai xe la : Xe di tfi Hai Phdng : Xi = 105 - 60t (1) Xe di tfi Ha Ndi: X2 = 75t (2) b) Hai xe gap Xi = X2 Giai (1) va (2), ta tim dugc t = 0,777 h « 46,2 ; x = 58,33 km e) Hgc sito tu ve dd thi 1« 1.0 ^ ^ m/s, (chuyen , dgng ,, cham u^ dan) ^ ^ a =- ^^2 -—^i) i - = (20 - 25) = - 2,5 1.9 a) Tuong tu bai tap trdn, ta tfnh dugc : a^j^ = = m/s^ (chuyin / ddng nhanh ddn) b) Khdng Gia tdc tinh dugc la gia tdc trung binh Nd'u gia tdc dd la khdng ddi thi chuyin ddng la biln ddi diu Khi dd trung binh cua hai vto td'e dtung bang vto td'e trung bito khoang thdi gian dd Tuy nhidn, ta khdng ed co sd dl ndi chuyin ddng cua chdt dilm la biln ddi diu 1.10 a) Chgn true Ox trung vdd dutog di cua dlectron Dung cdng thfic lidn hd gifla vdn td'e, dd ddd va gia tdc chuyin ddng thing biln ddi diu : V- VQ = 2a(x - Xg) = 2as Thay sd, ta cd : (5.10V - (3.10V = 2a.(2.10~^) Tfi dd suy gia td'e a » 6*25.10 m/s b) Cd thi dfing cdng thfic v = Vg + at dl tfto thod gian t Ta ed : ^ v - v g ^ 5.10^-3.10^ ~ a " 6,25.10^^ t«8.10~% Chii y : Ta todn thd'y, gia tde rdt Ito toung hat chi todn gia tdc mdt thod gian rdt tod (ed phdn ti giay) Gid tri la gia tri diln hito cfia gia tdc cac hat tfch didn cdc may gia td'e hidti 1.11 a) Chgn true toa dd trung vdd dutog di, gdc toa trung vdi vi tri cua ato cato sat giao thdng, gd'c thod gian la luc ato xudt phdt Khi dd d td da 93 d vi trf each ato cato sat 30 m Phuong trinh chuyin ddng cua d td va eua ato cato sat ldn lugt la : Xl = 30 + 30t (1) 3t^ x,= ^ (2) Khi ato cato sat dudi kip thi Xi = X2 Ta cd : 30 + 301 = — , hay la l,5t^-30t-30 = (3) Giai phuong trinh nay, ta dugc ti = 20,95 s vd t2 = - 0,95 s Vdy, sau 21 s anh cato sat dudi kip d td b) Thay t = 21 s vao cdng thfic (1) hoac (2), ta tim dugc qutog dudng; di dugc Kit qua la : s = 661 m Chii y : Cd thi giai bang ve dd thi '^'y2 c2 1.12 a) Tuong tu bai tdp 1.10, ta ed : a = = 3,6 m/s 2.70 , bidt s, a, Vg, ta tfnh duge t b) Dung edng thfie x - Xg = s = "Vgt +—at Kit qua la : t = 3,3 s 1.13 a) Phuang trinh chuyin ddng cua hai xe la Xe thfi todt: Xl = 40 + Vit = 40 + 40t Xe thfi h a i : X2 = V2t Lue dudi kip toau thi x"i = X2 = 200 km Cdng thfic (1) cho t = h Cdng thfie (2) eho 200 = V2.4 Tfi dd V2 = 50 km/h 94 - (1) (2) b) Dd thi (xem Hinh 1.3G) X (km) 250-200 100 6t(h) 1.14 Dung edng thfic v = Vg + at a) Ta cd a = m/s ; t = 2,5 s ; Vg = 5,2 m/s Thay vao cdng thfic trdn, ta dugc : V = 12,7 m/s b) Thay a = - m/s ; t = 2,5 s ; Vg = 5,2 m/s vao edng thfie tren, ta dugc : V = -2,3 m/s 1.15 Phuang trinh chuyin ddng cua chdt dilm la : X = -6t + 4t^ a) Thay t = s vao cdng thfic trdn, ta dugc : X = - 6.2 + 4.2^ = cm b) Vdn tdc V = - + 8t Thay t = s vao cdng thfie nay, ta dugc : v= 18 cm/s 1.16 a) V = 3.10^ + 8.10^^t = 5,4.10^ 10 Tfi dd suy rat = 3.10 '"s b) Cd thi dung mdt hai cdng thfie sau X = vot + ^* (1) 95 VJ x = ^ (2) 2a Thay sd vao cac cdng thfie trdn : (1) cho X = 3.10^t + 4.10^V ; vdi t = 3.10"^° s (2) cho X= L_[(5,4.105)2 - (3.10^)2] 2.8.10^^ Kit qua la : x = 1,26.10"'* m Quang dutog nhd nhung rd't Ito so vdd kfch thudc nguydn tu (10 m) ^ 1.17 a) Thdi gian nhd nhdt gia tdc can Ito nhdt, bang - m/s Ta ed : ^ ^ v - v g ^ 0-100^^^^ a -5 b) Quang dutog chay tren dutog bang cung la nhd nha't Ta cd : s = 100.20 + - (-5).20^ = 1000 m = km Nhu vay khdng thi eanh vdd dutog bang dai 0,8 km dugc 1.18* a) Chgn true Ox cd phuong thing dtog, hutog ldn trdn Gd'c toadg d mat ddt Phuang trinh chuyen ddng cua qua bdng la : X = Vgt - 4,9t^ Luc t = 1,5 s thi X = m Thay cae gid tri dd vao edng thfic trdn, ta cd : = vo.l,5-4,9.1,5^ Tfi dd suy : Vg = 10,0 m/s b) Ta ed V = Vg + (-9,8).t = 10,0 - 9,8.1,5 = -4,7 m/s Dd la vto tdc eua qua bdng ban bat duge Ddu trfi cd nghia la qua bdng dang roi xud'ng 1.19 a) Ta cd V = Vg - gt = Vg - 9,8t Thod dilm ti lue vdn tdc qua bdng bang 2,5 m/s la : v-4 2,5-4 '^ = ^ j = ^ : - = ^'^^^ ^ Thod dilm t2 luc van tdc dat gia tri -2,5 m/s (khi di xudng) btog : 96 Khotog thdd gian gifla hai thod dilm dd la : t = t2 - tl = 0,663 - 0,153 = 0,510 s b) Dd cao lfic dd btog toa dd cfia qua bdng : v^ - Vn 5^ - 4^ x-x„ = x = ^ ^ = ^ - ^ = 0,497m 1.20* Chgn true Ox ed phuong thing dtog hutog xudng dudd, gdc O tai vi tri tha vdt Ggi n la sd giay vat rod xudng din ddt Toa dd cua vat sau n gidy la : 2 Toa dd eua vdt sau ( n - l ) giay la : ^n-l = 2^1-1 =\s(n-if Trong gidy cudi cung (tfic la tfi luc (n - 1) giay dd'n luc n giay), vat rod duge 34,3 m, ta cd : /„ = 34,3 = x„ - x„_i hay la: /„= 34,3 = |.9,8[n2 - (n - 1)^] = 4,9.(2n - 1) Tfi dd tacd: 34 2n-1 = ^ = 7, hayn = vay thdi gian rod la s 1.21 Chgn true toa dd Ox cd gd'c tai vi tri tha hdn da va chilu hutog xudng dudd Phuong trito chuyin ddng cua hdn da va cua hdn bi thep Ito lugt la : xi = ^gt^ = 4,9t2 (1) X2 = V o t + | g t ^ = t + 4,9t^ ' (2) Khi hdn da rod din ddt, Xi = m, thdd gian rod la ti btog : • = j i = 1,277 s 7-BTVL 10(NC)->^ 97 Khi hdn bi thep rod xud'ng din ddt, X2 = m, thdi gian red t2 dugc tfnh theo edng thfic (2), tfic la : = 15t2 + 4,9t^, hay la 4,9t^ + 15t2 - = (3) Giai (3), ta dfige hai gid tri eua t2, ta chi ldy gia tri dfiong cua t2 btog : t2 = 0,463 s Hai vdt rod cdch toau khotog thdi gian la : At = tl - t2 = 1,277 - 0,463 = 0,814 s 1.22* Ggi h la dd sdu cua hang, ti la thdd gian hdn da red dto day, t2 la thdd gian tid'ng vgng tfi ddy hang ldn dd'n midng hang Ta cd : Tfidd h = Va^.t2 = 340t2 (1) h = - g t f = - t f =5tf ^ (2) 5t to=—I ••2 ^ 340 Thdd gian tfi luc tha hdn dd din lfic nghe thdy tidng vgng bang :, t = t i + t = 13,66 s Thay t2 vao bilu thfic vfia toto duge, ta cd : 5t2 ^ 340 hay la 5tJ + 340 tl - 13,66.340 = (3) Giai phuong trito (3), ta duge hai gia tri cua tj, dd cd mdt gia tri am Ta chi ldy gid tri duong ti = 11,66 s Nhu vay thdd gian tieng vgng di tii ddy hang din midng hang la : t2 = t - tl = 13,66 - 11,66 = s 98 l^BTVL 10(NC)* Dd sdu cua hang la : h = 340.t2 = 340.2 = 680 m 1.23* Chgn true toa dd cd phuong thing dtog, gdc O trfing vdd vi tri eua hdn bi lfic t = a) Sau s, hdn bi rod dugc mdt ddan Si = /i = :j.l0.1^ = m Sau s, hdn bi rod duge mdt doan dutog la : / = | 10.(2)^ =4.5 = 20 m Nhu vay giay thfi hai, hdn bi rod thdm dfige mdt doan la : S2 = / - / i = - = 15m Ta vilt lai tou sau : 52 = / - / i = 5(2^-1^) = 15 m Dd chinh la dd ddd eua hdn bi giay thfi Sau giay, hdn bi rod duge mdt doan dutog la : /3=|.10.(3)2=5.(3)V Nhu vay giay thfi 3, hdn bi da red dugc thdm mdt doan dutog la : 53 = /3-/2 = 5[3^-2^] = 25m S3 Cfing la dd ddd cua hdn bi giay thfi Ta tito duge dd ddd cua hdn bi giay thfi n : Sn = ^„ - ^n-1 = 5[n2 - (n - if] = 5(2n - ) m b) Ta cd: 52 - S l = 5[(2.2 - ) - ( - ) ] = 2.5 = 10 m 53 - S2 = 5[(2.3 - 1) - (2.2 - 1)] = 2.5 = 10 m Sn - s„_i = { ( n - l ) - [2(n - ) - ] } = 2.5 = 10 m v a y hidu cac dd ddd sau s lidn tilp b t o g 10 m, b t o g hai ldn dd ddd sau gidy thfi todt Ghi chii : Cd t h i dp dung cdng thfic d bai SGK la A/ = ax , dd ld'y A/ = Sn - Sn_i ; a = 10 m/s ; x = s 99 7.23 Nhung chd't long khdng dfto udt cdc 7.24* Giam di 1,2 lto, nghia la : ^^^^^ =1,2 a(d 80*'C) 7.25 0,075 N/m 7.26 0,0365 N 7.27* Luc etog bl mat cua nude lto hon luc etog bl mat cua rugu Luc etog bl mat eua nude thuc hidn edng duong Ai =0,0728.0,04.0,02 =582,4.10"^ J Lue etog bl mat cfia rugu thuc hidn cdng am A2 = - 0,0241.0,04.0,02 = - 192,8.10""^ J vay edng tdng cdng la : A = 582,4.10"'' - 192,8.10"'' = 389,6.10"^ J 7.28 816 kg/m^ 7.29 0,022 N/m 7.30 Trutog hgp A, mue ehdt long dtog cao 14,7 mm 7.31 Cdu A 7.32 Nudc sdi, vi nhidt hod hod lto hon toilu so vdd toidt lugng lam ndng nude 7.33* - Cdu A khdng dung vi cd cung nhidt cho mdt khdi chdt ma thi tfch cua nd Midng totog khdng ttog ma cdn giam di Chtog ban ta cung toidt dl lam ndng chay mdt cue nudc da Vi thi tfch riing cfia nudc da lto hon thi tfch ridng cua nudc ndn cue nude dd tan thi thi tfch eua nd giam - Cdu B khdng dfing vi ta cung nhidt dl khdi chdt ehuylh thi (ndng chay chtog ban) thi toidt cfia khdi ehdt dang ndng chay khdng ddi - Cdu C dung vi cung nhiet la su truyin ntog lugng dudd dang truyin nhidt - Cdu D khdng dfing vi frong ba cdu frdn chi cd mdt cdu dung 7.34 Cd tbl, chi cto hfit khf dl giam dp sudt tac dung ldn mat thoang cua nfidc 7.35 cau B Hudng ddn : Dung Bdng dp sudt vd khdi lugng rieng ctia hai nudc bdo hod a nhiet khdc (xem bai 56 SGK) va ndi suy ttong khotog nhidt dd 25°C-30°C 7.36 25°C thi dfige, cdn d 35°C thi khdng, vi toidt dd 35*'C cao hon nhidt dd tdd ban cua CO2 156 7.37.1 atm ; dp sudt bed bao hoa ehi phu thudc nhidt dd, khdng phu thudc thi tfch 7.38* Cd toflng each sau ddy : a) Lam lato dtog tfch din 284 K b) Nen dang nhidt dd'n 23,3 lft e) Lam ddng thdd ca hai each trdn, nghia la vfia nen vfia giam nhidt 7.39 4,8 tdn 7.40 60 kJ/kg 7.41 120,62 kJ 7.42 64,4 kg ; dung phuang trito Cla-pd-rdn -Men-dd-ld-ep suy edng thfic : p = : ^ va tfto duge p = 6,77 kg/m^ RT -2 o 7.43 a = 10 g/m ; A = 12,8 g/m (tra Bdng dp sudt vd khdi lugng rieng cua hai r% nudc bdo hod d nhiet khdc SGK); f = — =78% 7.44 Tang thdm 23% 7.45 11J[°C Nhiet dd ma d dd d kfnh cfia sd md di la diem suang cua khdng dm 7.46 0,4 m^ 7.47 64% 7.48 72% va 76% 7.49* 17°C Hu&ng ddn : Hai nhidt kl ehi nhidt dd gidng toau thi dd dm ti ddi la 100% Luc dd, Im^ khdng khf dm cd 12,8 g hod nudc 2b°C thi lugng hod nude bao hoa la : 17,3 g/m (xem Bdng dp sudt vd khdi lugfng rieng cua hai nudc hdo hod nhiet khdc SGK) Vay dd dm ti ddi la : f = i | X 100 = 74% Nhidt k l khd chi 20°C ma dd dm ti ddi la 74% tiii theo 17,3 Bdng tra dd dm ti ddi (xem bai 56 SGK) su chdto Idch toidt dd gifla hai nhidt k l la 3°C Vay ddp sd la 17°C 7.50* Trutog hgp C, dd dm ri dd'i la 92,4% 157 7.51 - Kep hai tdm thuy tinh song song each btog cae thto que didm (trudc'dd phai lau sach hai mat ddi didn dl dam bao dfto udt) - Nhung toe mdt canh cua hai tdm cham mat nudc cua khay, thdy nudc dang ldn d gifla hai tdm thuy tinh - Do cao cfia phdn nudc dtog ldn va tfto hd sd etog bl m^t cua nudc , - , 4a pghd theo cong thuc h = , suy a = ^-^— pgd 7.52 - Nd'i hai d'ng thuy tinh thdng vdd btog d'ng cao su - Dd nudc vao dng, chd cto btog, dd cao hi tfi mat thotog ddii midng dng tod - Dung nut bit kfn ddu dng tod, ntog dng cao ldn, dd : + BChd'i khf ddu dng tod bi giam va bi nen dtog nhidt + Mat thoang hai ben chdto Idch Ah + Do cao cdt khf bdn dng tod la h2 - Tfto Pa (dp sudt khf quyln) theo phuong ttinh dang nhidt se dugc : ^pghjAh ^' hi-h2 ,^ - Dfing thudc Ah, hi, h2 se tfto dugc dp sudt khf quyln 7.53 - Nhung d'ng thing dtog vao chdt ldng - Do dd cao hi tfi mat thoang dd'n midng dng (cfia cdt kjif ban ddu) - Gifl nguydn vi tri d'ng, bit ddu trdn cfia d'ng (giam khdi khf d ddu d'ng) - Tfi tfi tod'c dng ldn cao theo phuong thtog dtog din ddu dudi dng gdn ldn din mat thodng Do dd cao h2 Cua cdt khf bi giam d ddu trdn cua d'ng, va h la dd cao cdt chdt ldng ttong dng so vdd mat chdt long ttong binh - Day la qua trito dan ding toidt, ed tbl tfnh duge khdi lugng ridng theo cdng thfic : - ^ Pa(h2 - hi) ^ ghh2 - Dung thudc dugc cdc gid tri h^ h2, h 158 CO s d cun NHICT DONG LlfC HOC 8.1 Trutog hgp D 8.2 Vidn thfi todt, vi toan bd ddng nang chuyin sang ndi nang 8.3 Hdn hgp khf d cudi ki nen Nlu coi cac khf nhu khf If tutog thi ndi ntog cua khf chi phu thudc toidt dd Nhidt dd cfia cac khf d.cudi ki nto cao hon nhidt dd cua cdc khf d cud'i ki thoat, 8.4 800 W 8.5* At = 9v' ; dd c la toidt dung ridng cua chi 8c 8.6 0,11 K 8.7 8,15 K 8.8 357 m/s 8.9* Theo cdch a thi qua trito AiBi la qua trito dtog nhidt Theo each b thi nto nhanh khf ndng ldn (vi toilt toa khdng kip), dutog bilu didn la dutog AiCBi bdn trdn dutog AiBi (Hinh 8.lG) Theo each b cdng nin lto hon vi dutog bilu diln qud trinh ndm ttdn dutog ding toidt AiBi 8.10 Day C 8.11* Cach A Hudng ddn : Dfing dd thi p - V dl bilu thi cdng cua khf cac each da ndu rdi so sanh cdng d mdi cdch btog cdch so sato cdc didn tfch nam dudd cac dutog bilu didn 159 8.12 Nhidt lugng cung cdp cho khf ttong qud trinh dtog dp, ngoai vide dfing dl lam ndng khf cdn dung dl khf sinh edng dan 8.13 396 kJ Tfto theo cdng thfic : A' = pAV ; AV la phdn thi tfch ttog thdm cua khdng khf phdng duge sudd ndng dtog dp Khdng khf ndng thoat khdi phdng qua cac khe hd 8.14* 3,3.10^ J; 6,1.10^ J Hudng ddn : Phuong trinh cua nguydn If thfi todt ddi vdd qud trinh dtog dp la Q = AU - A Trude hit, ta phai tfto cdng A' cfia khf dto ding dp Ddi vdd trang thai ddu va cudi cua khf, ta vilt pVi = vRTi va pV2 = VRT2 Trfi hai phfiong trito cho toau, ta ed p(V2 - Vi) = vR(T2 - Ti) V I phai cho phep ta tfto cdng cua khf dto dtog dp vi v l ttdi la bilu thfic tfto cdng vay : A' = 800.8,31.500 = 324000 J A' « 3,3.10 J Cdng khf sinh 8.15* 49 J Hudng ddn • Trude hit dp dung dito ludt Sde-lo dd'i vdd hai qua trito dang tfch, ta tim dugc T^ = T2T4, ttong dd T la toidt dd cua qua trinh dtog nhidt Mud'n tfnh cdng ma khf thuc hidn chu trito, ta tfto didn tfch hinh chft nhdt i234 Bilu thfie tfto edng cua chu tiito la A' = R[ T2+T4 - 2(T2T4)^^^] Xem thdm|iutog dto cua bai 8.14 8.16 760 W 8.17 cau C 8.18 24% ; 42% 8.19 113,5 kJ; 28,4 kJ 8.20 84 kJ ; 14,1 kJ 8.21 Cau C : vat bang chi, vi chi ed nhidt dung ridng be todt 8.22 Cdu C : vdt bang niken, vi niken cd khdi lugng ridng lto todt 8.23* - Cdu A sai vi ndi nang cua hd khf If tudng khdng bao gdm thi ntog tuong tde giua cdc hat cdu tao ndn he 160 - Cdu B sai vi toidt lugng truyin cho hd cdn cd tbl lam ttog tuong tdc gifla cdc hat edu tao ndn hd Vf du ta cdp toidt dl lam cho hd chuyin trang thai Lfic dd toidt dd khdng tang ma tbl ndng tang vi cd su thay ddi cdu true bdn bd - Cau C dung Vf du ta nto khf thi ta vfia lam khf ndng len vfia giam tbl tfch khf - cau D sai vi nlu cho khf If tutog dan vao chan khdng thi ndi nang cua hd khdng ddi ma tbl tfch eua hd tang ldn 8.24* - Kf hidu binh cd nudc ban ddu la X, bito la Y - Dat X vao nudc ndng, Y vao nudc lanh, nudc se chay tfi X sang Y (do khf bi nd ndng va eo lai lato) - Chd dd'n ngtog chay, ddi chd X vao nudc lato, Y vao nudc ndng Do dng thuy tihh d Y ngdn ndn nude khdng chay ngugc ldn dugc ma chi cd khdng khf tran tfi binh Y sang binh X - Lai ddi chd hai binh, nudc lai chay thdm tfi X sang Y - Cd tbl lap lai nhilu lto dl ttog hidu qua MOT SO nni Tnp TONG HOP V€ CO NHICT Ap dung dinh luat bao toto co ntog : mv = mgh dd v la vto tdc cua qua cdu d dilm thdp nhdtB h = HB = / - /cosa Tfi dd:v^ = g / ( l - c o s a ) H V -* (1) B pt Hinh I G Tai vi tri thdp todt cfia qua edu (Hito IG) : T - P = Fh^ f v^ T =m g+ - M I—— (2) Thay (1) vao (2) ta dugc : T = mg(3 - 2cosa) = 2,49 N Do lto cfia T khdng phu thudc gia tri cfia chilu dai / cua ddy Vi m^ = mg va lue ma sdt khdng dang kl, ndn chdc chto la vdt B di xudng, keo vdt A di ldn Ap dung dinh ludt II Niu-ton cho mdi vdt: Vdt B : mg - T = ma Vdt A : T - mgsina = ma Giai he ta dugc : a= - g ( l - s i n a ) (1) T = —mg(l + sina) (2) Vdy cdng sudt tfic thdd cua lite etog T tai thdd dilm t la : g'=Tv = Tat Thay (1) va (2) vao (3) ta dugc : g' = -^mg^tcos^a « W 162 ' (3) a) Giai btog phuong phap ddng luc hgc Dua vao phep phto tfch luc va dp dung dito ludt II Niu-tan, ta tfto duge gia tdc cua vat lfic di ldn (ehilu duong ldy theo chilu chuyin ddng): = -g(sina + pjcosa) Qutog dutog vdt di ldn : 0-v? s= ^ ' v2 V? 2ai (1) 2g(sina + pj cosa) Gia tde cua vat luc diL xudng : a2 = g(sina - Ptcosa) Quang dutog vat di xud'ng : v?-0 vi (2) S = -42a2 : 2g(sina - PfCosa) Giai hd phuang trinh (1), (2) vdd cac to pj va s, ta dugc : _ Pt = ^—^tana = 0,28 ^ (3) vf+v^ 2 vf + V^ 4gsma 2 vf + VT Do dd h = s.sina = -^—« 0,64 m (4) 4g b) Giai bang phuong phdp ntog lugng Chgn md'c tfto tbl nang d A Khi vat di ldn, cdng cua luc ma sdt btog dd bid'n thidn co nang : ^ms = Wg - W^, hay : -sptmgeosa = mgh mv^ ^^ (5) Khi vat di xudng, edng cua luc ma sat cung btog dd biln thidn co nang : Ams = WA - WB , hay : -sptingeosa = - ^ - mgh (6) Giai hd (5), (6), ta cung dat dugc cdc kit qua tou (3), (4) 163 4* Vdt chiu tac dung cua frgng lue P va phto luc phdp tuylh N cua ban cdu : P + N = ma Khi vdt rdi bl mat ban cdu thi N = , dd P = ma Chid'u xud'ng phuong cfia ban kuih BO : mgcosa mv Hinh ehilu cfia a trdn phfiOng ban kfnh la gia tdc hutog tdm Dp dd : V = grcosa = gh (1) Ap dung dinh ludt bao toto eo ntog mgr = mgh + mv Hinh 2G (2) Thay (1) vao (2), ta thu duge : h r Luc ddu cac khf bong bdng xa phdng cd nhidt dd cao hon khdng khf (hod thd cfia ngudd cd nhidt 37°C) va lue dd luc ddy Ac-si-met cfia khdng khf lto hon frgng lugng cfia bong bdng xa phdng, lam cho bong bdng bay ldn Sau dd, bong bdng xa phdng giam nhidt dd toa nhidt Ifigng khdng khf va thu tod tbl tfch bong bdng lai ndn luc ddy Ae-si-met tod dto di, cdn trgng lugng cfia bong bdng xa phdng thi khdng ddi Din mdt lfic nao dd thi frgng lugng cfia bong bdng xa phdng lto hon luc ddy Ac-si-mit, kit qua la vdn tdc di ldn eua bong bdng giam dto rdi tfi tfi rod xudng O frang thdi khdng trgng lugng, khdi thuy ngto (khdng dfnh udt thuy tinh) CO lai thato dang hinh cdu ; cdn khdi nudc (dfto udt thuy tinh) loang frdn toto bd mat frong eua binh ehfia Mdi giay blp didn cung cdp cho nudc ttong dm mdt nhidt lugng la : Q = 0,8.1000 = 800 J Nhidt lugng lam hod hod mdt lugng nudc btog : 800 m = -— = « 0,354 g L 2,26.10^ 164 I Thi tfch eua lugng bed nudc dugc tao ttong gidy la : ^0,354 8,31.373- = ^^^^^o< V = mRT = ———,— 0,000595 m3 » ^nnn^ 0,000 m3 1^ P 18 1,013.10^ Tdc dd hod phut raid : V 0,000595 , ^ = ^ = -o;ooor = ^'^^"^/^ Hod nudc sdi thoat ngoai khdng qua trito ding dp nen ta ed tbl tfto cdng cua hod nudc (tao tfi Ig nudc) chid'm thi tfch V theo cdng thfic : A = pAV = pV = - R T = ^ : ^ ^ - 172,2 J p 18 8* Ta tfnh luc ddy Ac-si-met F^ ldn khf cdu Luc bing trgng lugng cua thi tfch khdng khf dm bi chid'm chd Bdy gid ta tfto khdi lugng ridng cua khdng khf dm p', nd btog khd'i lugng -3 ridng cua khdng khf khd p cdng vdi lugng bed nudc ed ttong m khdng Theo cdng thfic f = -^ = ^'^' "^^y ^ = ^'^ ^• Theo Bdng dp sudt vd khdi lugfng rieng cua hai nudc bdo hod d nhiet dd khdc (xem SGK, bai 56) thi A = 17,3 g/m vay : a = 0,8.17,3 = 13,84 gim Bay gid ta tfnh khd'i lugng ridng eua khdng khf khd Tfi phuang trito Cla-pd-rdn - Men-dd-ld-ep, ta rfit : m pp 10^29 ,„ ,3 P=V =1^=831293=1'''^/"^ Tfi dd p' = p + a = 1191 + 13,84 = 204,84 givn FA = (p'.64)g = 77,110.9,8 = 755,678 N Lfic ntog khf cdu la : F = (77,110 - 55).9,8 « 216,6 N Dd dto cua ddy thep dugc tfnh theo edng thfie cfia dinh luat Hue F i.^^ A/ / I F cn 216,6 ^ ^ ^ ^ ^ _ — = E-r-, suy : A/ = /g—— = 50 — z « 0,025 m S /g "ES 2,1.10" 2.10-^ vay A/« 2,5 cm Ggi mi va m2 la khdi lugng cue nudc dd va lugng hod nudc sdi dua vao toidt lugng kl Ta cd : mi + m2 = 500 g Suy : m2 = 500 - mi 165 Ta thilt ldp phuong trito c t o bang toidt lugng : - Nhidt lugng ma cue nude da va nude ttong nhidt lugng k l todn vao la : Qi = mic'iLO - (-5)] + miX + m^ c'l (25 - 0) + 300 C2 [25 - (-5)] - Nhidt lugng ma lugng hoi nudc toa la : 10 Q2 = (500 - m i ) L + (500 - m ^ c ' i ' ( 0 - ) Vi cac dd l t o eua Qi va Q2 phai btog toau, ta cd : 5mici + m^X + 25miei + 30.300e2 = (500 - mi)L + 75(500 - mi)ci dd c\ va Cj la nhidt dung ridng cua nudc da va nude, cdn 02 la nhidt dung ridng cua todm Thay cdc gia tri da bilt vao phuong trito frdn va giai ra, ta dugc : Khdi lugng cue nude dd mi = 423,1 g Khd'i lugng hod nude m2 = 500 - 423,1 = 76,9 g Nguydn tdc sudd dm ddng lue duge bilu thi d so dd dudd ddy : H„ A^ T - Tl , T-Ti I -> A' = Qi h Qi T1-T2 Q2=A vTi nhift H# Mng sudi , suy : = Q '2 J Opng CO T-Ti ^ _ Q i | /" T Q^ = Qi - A' = Qi A ^ M&y lenh (T-Ti)T2 T(Ti - T2) T-T, Ta vilt dugc tou trdn la vi lAI = IA'I = Qi — = - ^ ( v d i T > Ti) He thd'ng sudi toto toidt lugng : Q = Q2 + Qi O ' - A + O - Q ^-^^ J Q1-A + Q2-Q1 ^^-^i^^2_Q Ti(T-Ti) +^iT(Ti-T2)~^iT(Ti-T2) Tdm lai: Q = Q^ + Q'l = Qi ^ [ j ^ ^ • Ap d , n g s d : Q i = 6000 kcal thi Q = Q i i | [ | | ^ ) Q « 2,98.6000 « 18000 kcal Nhu vay sudi dm ddng luc lgi ban toilu (gdp g t o ba ldn) 166 Hinh 3G MUC LUC Trang Ldd ndi ddu PH^N MOT : DE BAI ChuangI Ddng hge ehdt dilm Chuang II Ddng luc hgc chdt dilm Tito hge vat rdn -Chuang III Cac dinh luat bao toan Chuang IV Co hge ehdt luu ChuangV Chd't khf Chuang VI Chuang VII Chdt rdn va chdt long Su chuyin tbl 'Chuang VIII Co sd cfia nhidt ddng luc hgc Mdt sdbdi tap tdng hgfp ve ca vd nhiet PHXN H A I : Hir6NG DAN GIAI VA DAP SO ChuangI Ddng hge chdt dilm Chuang II Ddng lue hge ehdt dilm Chuang III Tinh hge vdt rdn Chuang IV Cae dinh luat bao toan ChuangV Co hge cha't luu Chuang VI Chdt khf Chuang VII Chat rto va cha't long Sir chuyin tbl Chuang VIII Co sd cua nhidt ddng luc hge Mdt sdbdi tap tdng hgp ve ca vd nhiet 18 31 40 59 65 71 82 88 90 90 106 122 129 146 150 154 159 162 167 Chiu trdch nhiem xudt bdn : Chu tich HDQT kiem Tdng Giim d6c NGO TRAN AI Pho T6ng Giam d6c kiem T6ng bien tap N G U Y I I N QUt THAO Bien tap ldn ddu : NGUYfeN TIEN BINH - VU THANH MAI Bien tap tdi bdn: D THI BICH L I £ N Bien tap Id thudt: CAO LAN PHlTONG - DINH XUAN DUNG Trinh bdy bia : TA THANH TtJNG Sica bdn in : D THI BICH LifiN Che bdn : CONG TY CP THI^T K£ VA PHAT HANH SACH GIAO DUC BAI TAP VAT Ll 10 NANG CAO Ma s d : NB006T0 In 10.000 ban, (Qe44BT) khd 17 x 24 cm In tai Cong ty.co phan in Son La Sd in: 10SL sd xuat ban 01-2010/CXB/639-1485/GD In xong va nop luu chilu thang nam 2010; 168 •Xl-B QUALITY CROWN VaONG MIEN KIM CUONG C H A T LI/0NG QUOC TE HUAN CHl/CJNG HO CHI MINH SACH BAI TAP LCfP 10 BAI TAP OAI SO 10 B A I T A P T I N H O C I O BAI TAP HiNH HOC 10 B A I T A P T I ^ N G A N H I O B A I T A P V A T L I I O BAI TAP TI^NG PHAP 10 BAI TAP 10 HOA HOC BAI TAP TI^NG NGA 10 BAI TAP NGff VAN 10 (tap mot, tap hai) SACH BAI T A P L O P 10 - NANG CAO BAI TAP OAI S 10 BAI TAP HINH HOC BAI TAP VAT LI 10 10 BAI TAP HOA HOC • BAI TAP 10 NGUrVAN 10 (tap mot, tap hai) BAI TAP TI^NG ANH 10 Ban dpc co the mua sach tai: • Cac Cong ty Sach - Thiet bi tnroTig hoc a cac dia phuofng • Cong ty CP Diu tu va Phat triSn Giao due Ha Noi, 187B Giang Vo, TR Ha Noi • Cong ty CP.Dau tu va Phat trien Giao due Phuomg Nam, 231 Nguyin Van Cu, Quan 5, TR HCM • Cong ty CP Dau tu va Phat tri8n Giao due Da Nlng, 15 NguySn Chi Thanh, TP Da Nlng hoac cac cua hang sach cua Nha xuat ban Giao due Viet Nam : - Tai TR Ha Noi : Tai TR Da Nang : - Tai TR H6 Chi Minh - Tai TR Can Tho 187 Giang Vo ; 232 Tay Son ; 23 Trang Tign ; 25 Han Thuyen ; 32E Kim Ma ; 14/3 Nguyin Khanh Toan 78 Pasteur ; 247 Hai Phong 104 Mai Thi Luu ; 2A Dinh Tien Hoang, Quan ; 240 Trkn Binh Trong ; 231 Nguyen Van Cu, Quan ; Binh Thai, Quan 11 5/5 Duong 30/4 Website: www.nxbgd.com.vn 934980"0 06399 Gid: 7.600 d ... : (5.10V - (3.10V = 2a.(2 .10~ ^) Tfi dd suy gia td'e a » 6*25 .10 m/s b) Cd thi dfing cdng thfic v = Vg + at dl tfto thod gian t Ta ed : ^ v - v g ^ 5 .10^ -3 .10^ ~ a " 6,25 .10^ ^ t«8 .10~ % Chii y :... = 3 .10^ + 8 .10^ ^t = 5,4 .10^ 10 Tfi dd suy rat = 3 .10 '"s b) Cd thi dung mdt hai cdng thfie sau X = vot + ^* (1) 95 VJ x = ^ (2) 2a Thay sd vao cac cdng thfie trdn : (1) cho X = 3 .10^ t + 4 .10^ V... 3 .10^ t + 4 .10^ V ; vdi t = 3 .10" ^° s (2) cho X= L_[(5,4 .105 )2 - (3 .10^ )2] 2.8 .10^ ^ Kit qua la : x = 1,26 .10" '* m Quang dutog nhd nhung rd't Ito so vdd kfch thudc nguydn tu (10 m) ^ 1.17 a) Thdi gian