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111m2kmdmcmmmmnm21km1000m=103m1dm0.1m=10-1m1cm=10-2m1mm=10-3m1m=10-6m1nm=10-9m3:1,,23,4Sminh51min=60s1h=60min=3600s6781239123101234122:3(1)(2)(3)(4)12vStS------mkmt-------shV------m/skm/h3SVttSV41m/s=3.6km/h515m/s15m6789101212123341234m/sVSt15340m/s;10.1s21HZ231220Hz20000Hz20000Hz20Hz34B54112234dB90dB0dB51()2312B31210C200C1000C00C1000C10010C30C200C202015350C420C0.10C12121AB2B480C3BC4C480C5CD6DE7E480C8EF9F480C10FH1.2.16231abc,abcdabcd4541251231020304571(2;3121234312c=3108m/s33c42c/3419.461015m100m10012312iri90r903824004512361231[2]23912123123045612123410D1212O3F4f1231112312(u2f)123fu2f120ufuvu2ffv2fu=2fv=2ffu2fv2fu=f0ufvf1234125uv2f4f6fu2f0uf12kg(g)(mg)(t)31kg=103g1mg=10-3g=10-6kg1t=103kg4511).(,,)2)3),,.2:12,,,3(,,,)(3):1).()2),,3131.23=m/v4/3kg/m3/3g/cm351/3103/31103kg/m3=1g/cm31L1dm310-3m31ml1cm310-3L10-6m361.0103kg/m3,1.0103.7,,,,.81mv23vm/91Am1Bm2CVDm/Vm1m2V2AmBV1CV2Dm/Vm/(V2V1)3AmBV114CV2Dm/(V2V1)Am0Bm1Cm2Dm/Vm2m0m1mo123121421215f=u/2=v/234456(17),7.16