第十一届非物理类专业大学生物理竞赛试题及解答-1994

(1994):(120).1517.(100).(52)11(4),.21(4)51010-4cm,.5000~,.6000~,.31(5),S0,.S0P,S0;S1S2Q1Q2,,.PQ1Q2,,.41(4)DK,,,d.L,.()51(4),,.,,.61(6)u1,u2.M0S,vu1,B,SM1=,B901M2=.(SBv)SõvBõ71(4),,P,v0.a=g,P,v=..81(6)aABCB,,aABCt=0,T.ABC.ABCA,.ABCR,t=0t1=Tö6I1=.t=0t2=Tö2I2=.91(5)B,.hMN,Mmq0P.P.,Pu.,PN,R=..101(5)R1eE0$E=.111(5),R,Oa(aR),q,,q=.(20)121(10)M,,.,mv,vU=45,,:011(1);(2)a,,22amv(M+m)v131(10),PVO,PV.:.(30)141(15),2mO,,12m2m,.,L.,,L=0,;L0,,,;LL0,,L0.151(15)ABdAB,A4Q(Q0),BQ.MN,MN,.,PA,PB,PAx.(18)161(5),:115V.?.171(5).3mA,108;0175V,215k8;,()01045mA,()010075V.6,.111(V)0.2000.4000.5000.6000.6200.640(mA)0.080.160.250.741.452.90181(8)R,5.R().(V)0.0000.1350.1800.2450.750(mA)0.000.100.150.200.60(52)11(4):vp=2kTmf(vp)=4Pm2PkT3ö2õ2kTmõe-m2kTõ2kTm=4ePõ(m2kT)1ö2mN2mH2(vp)N2(vp)H2(f(vp))N2(f(vp))H2.21(4)13.:dsinH=kKsinH=kKdûsinHû1,-1kKd1K=6000~,-812k812.,K=6000~,.174,8,13.31(5)(),.:S0P,,;S1,S2Q1,Q2,e,o,P,().,.41(4)D2d2ö5.96L2K2:H·1122KD,R·1122KLD,,:P(d2)2PõR2=(d2)2(1.22KLD)2=D2d25.96L2K251(4):,vs,u(uc),,.,vsu,211.61(6)M1=u1-vu1+vM0,M2=M0:S,vM=u1-vu1M0(1)SM1=u1u1+vM(2)B(,,)M2=u1u1-vM(3)(1)(2)M1=u1-vu1+vM0(1)(3):M2=M071(4)2v0:,(1),v0=2gl,,ma=mg.(2).F,2mg,a=45;F.g=2gh=2l.,Pv=2gh=2(2g)(2l)=2v081(6)3Ba2ö2RT;13I1=Ba2ö23RT:t=0t1=Tö6,ABCABC1,2,3,:$5=-13BõS=-13Bõ(34a2)=-312a2BE=-$5$t=312a2BT6=3Ba22TI1=ER=3Ba22RT0.,t=0t2=Tö2,$5$5=$5,$t=T2=3113$tI2=13I1=Ba223RT0.91(5)muqB1+2qBhmu:Pu,u,B,MN,Ph.f=quB,a=föm=quBömNMNv2=2ah=2quBhmu,N,v2=v2+u2v=u1+2qBhmuR=mvqB=muqB1+2qBhmu101(5)e2ö8PE0R1:E1=12mv2-e24PE0R1(1)mv2R1=e24PE0R21(2)(1)(2):E1=-e2ö8PE0R1$E=E-E1=0-(-e28PE0R1)=e2ö8PE0R1111(5)-Raq:,,U=U=0U=q4PE0a+dq4PE0R=q4PE0a+q4PE0R=0q=-Raq(20)121(10):(1),.U=45,22a,.(2),,CMu,VC=muM+m.T=(422õa)öv=22aöv,C:S=VCT=mvM+mT=22amvö(M+m)vC,S.131(10):ABCA,AB,PV-1=K(1)KAB.,AB:Q=$E+A=MCV(TB-TA)+VBVAPdV(2)(1)411PV=MRT(3):T=KV2MR(4)(1),(4)(2):Q=KCVR(V2B-V2A)+K2(V2B-V2A)=K(CVR+12)(V2B-V2A)(5):W=12(PB-PA)(VB-VA)=K2(VB-VA)2(6)(5)(6)G=WQ=K2(VB-VA)2K(CVR+12)(V2B-V2A)=VB-VA(2CVR+1)(VB+VA)(7)(7),GABK,K,G.:ABCA,AB,PV-1=K,KAB.n=-1,:C=CV(C-n1-n)=CV2(C+1),C=CpöCVCK.ABQ=MC(TB-TA)(1)PV=MRTPV-1=KT=KV2öMR(2)(1),(2):Q=CKR(V2B-V2A)(3)W=12(PB-PA)(VB-VA)=12K(VB-VA)2(4)(3)(4)G=WQ=R(VB-VA)2C(VB+VA)(5)(5),GK;K,G.(30)141(15):1,2,:T1-mg=ma(1)2mg-T2=2ma(2)T2R-T1R=mR2B(3)a=BR(4):df=T(H+dH)cosdH2-T(H)cosdH2=dT(5)dN=T(H+dH)sindH2+T(H)sindH2=TdH(6)LL0:df=L0dN(7)(5)(6)(7)dT=L0T(H)dHT2T1dTT(H)=P0L0dH511:T2=T1eL0P(8)(1)-(4),(8):L0=1Pln65151(15):PBABS,;S:4Q4PE0r21=Q4PE0r22(1)r1+r2=d(2)P,S,,PS,,:4Q(-q)4PE0x+Q(-q)4PE0(x+d)=4Q(-q)4PE0r1+Q(-q)4PE0r2(3)(1)(2)(3):x=29(10-1)d,r1=23d,r2=13dPBWBSWS,PB,B.WB=4Q(-q)4PE0d+Q(-q)4PE0RB=-Qq4PE0(4d+1RB)WS=4Q(-q)4PE0r1+Q(-q)4PE0r2=-Qq4PE0(4r1+1r2)=-Qq4PE0õ9dRBnd4d+1RB9dWBWS,PB.(18)161(5):,,;,,,;,;;.171(5):,,.IA,IVIDIA=IV+ID=URV+IDID=IA-URV,RV=2.5k8:U(V)0.2000.4000.5000.6000.6200.640IA(mA)0.080.160.250.741.452.90ID(mA)000.050.501.202.64UID,().181(8):5,4,5,5.:R=(IU-1RV)-1=(0.6010-30.75-12500)-1=25008$RR=(5R5U$U)2+(5R5I$I)2=($UU)2+($II)2ö(1-UIRV)611=(0.00750.75)2+(0.0450.6)2ö(1-0.750.62.5)=0.012+0.0752ö0.5·0.15R=(2.50.38)k8:$RR=1R(û5R5U$Uû+û5R5I$Iû)=($UU+$II)ö(1-UIRV)=(0.01+0.075)ö0.5=0.17R=(2.50.43)k8:711