wuhoudeyangguangtouguolaojiudebolichuang，lanyangyangdisazaijiangchengzhongdianzhongxuegaoer（san）bandejiaoshili，jiangkongqizhongfeiwudefenbichenairanchenglexisuidejinse。jiangtaishang，wulilaoshizhangjianguoneilvedaishayadesangyin，zhengrutongyongbutingxiedecuimianqu，jiangjiezheguanyuyunbiansuzhixianyundongdegongshituidao。v=v₀+at，s=v₀t+½at²……shuxidefuhaohedinglv，cikezailuyangyanzhongquerutonggezheyicengmoshaboli，jiqingxiyoumohu。
tadeyishi，xiangyisouganggangjingliguojingtaohailangdexiaochuan，haizaijuliediyaohuangzhe，shangweiwanquankaoan。wushinianderenshengjiyi，neixieshibai、huihen、bugan，rutongchaoshuibanfanfuchongshuazhezheijujinyoushiqisuidenianqingquqiao，dailaiyizhongnanyiyanyudegelieganhexuanyun。tanengganjuedaoxinzangzaixiongqiangli“dongdong”dikuangtiao，xueyebenyongzhechongxiangsizhibaihai，dailaiyizhongjimoshengyouchongmanhuolideganjue，danzheixianhuodeshengmingli，quebeiyigebaojingcangsang、pibeibukandelinghunsuojiayu。
tabixuwenzhu，bixuxiangyigezhenzhengdeshiqisuishaonianneiyangzuozaizheili，bunengluchurenhepozhan。luyangqiangpozijijiangmuguangjujiaozaiheibanshangneiyixingxingcangjingyoulidefenbizishang，shituyongketangdezhixuganlaimaodingzijihunluandesixu。tashenzhikaishiwuyishidimofangzhezhouweitongxuedezitai——yourenzairenzhentingjiang，fenbijishu；yourentoutouzaidixiakanxiaoshuo，yongkebendazheyanhu；qianpaidewanglei，neigejiyizhongzongshixixihahadejiahuo，cikezhengbanaodaimaidedidide，gujiyouzaidakeshuile。
ertashenpang……luyangdeyanjiaoyuguangbuyouzizhudipiexiangleyouce。suxiaomanzuodebizhi，wuheidemahuabianchuizainaohou，luchuyiduanbaixixinidebojing。tazhengzhuanzhudikanzheheiban，ouerdixiatou，yongneizhikanqilaihenputongdeyingxiongpaigangbi，zaibijibenshangfeikuaidijiluzheshenme。yangguanggoulechutarenzhendecelianlunkuo，zhangzhangdejiemaoxiangliangbaxiaoshanzi，weiweizhandong。qianshi，zheigenvhaijiuxiangyidaoyaobukejideguang，zhaoliangletahuianqingchunliweishubuduodejiaoluo，queyerangtazicanxinghui，bugankaojin。zheiyishi……
bu，xianzaibushixiangzheixiedeshihou！luyangmengdishouhuimuguang，xinzhongjinglingdazuo。taxianzaijiuxiangyigehuaichuaizhejingtianmimidejiandie，qianfuzaidiyingzhizhong，renheyisiyichangdeqingxuliulu，doukenengyinlaihuimiexingdehouguo。
tashenxiyikouqi，shitujiangzhuyilizhongxinlahuidaowulikeshang。zhanglaoshideshengyinsihubiandeqingxileyixie：“……suoyi，genjuzheigegongshi，womenkeyituidaochu，dangwutizuoziyouluotiyundongshi，tademosuduzhiyuxialuodegaoduyouguan，eryuwutidezhiliangwuguan。zheiyidian，jialilvezaibisaxietashangyijingzuoguozhumingdeshiyanzhengmingle……”
ziyouluoti……zhiliangwuguan……
luyangdesixuyouxiepiaohu。tazijidelinghun，buyexiangshizaizuoyichangguiyideziyouluotiyundongma？congwushisuideshengmingzhongdian，haowuzhengzhaodizhuiluohuileshiqisuideqidian。zheiyoushizunxunlenamenzidewulidinglv？
jiuzaizheishi，neigebingleng、haowuganqing、fangfozhijiexiangchezailinghunshenchudeshengyin，haowuyuzhaodizaicixiangqi，rutongzaipingjingdehumiantouxialeyikejushi，shunjiandapoletanuliweichidecuiruopingheng。
【“‘qizhi’xitongzhengshijihuo。”】
luyanghunshenmengdiyijiang，wozhebideshouzhixiayishidishoujin，zhijieyinweiyonglierweiweifabai。laile！neigezaitayishixiaosanqiantigong“huigui”xuanzedeshenmishengyin！tadaodishishenmedongxi？！
taqiangpozijiweichizhetingkedezishi，lianyanpidoubuganduozhayixia，shengpabeijiangtaishangdezhanglaoshihuozhezhouweidetongxuechajuedaorenheyiyang。dantadeneixin，zaoyixianqiletaotianjulang。xitong？shenmexitong？youxima？haishi……mouzhonggengwufalijiedecunzai？
neigeshengyinbingmeiyoulihuitaneixindejingtaohailang，jixuyiyizhongchuncuiluojihua、budairenherenleiqingganbodongdeyudiao，zaitadeyishizhong“shushuo”zhe：
【“shibiedaihao：qizhi。”】
【“xingzhi：qiangrengongzhinengfuzhudanyuan。”】
【“bangdingxieyi：jiyuliangzijiuchanyuyishiyingsheyuanli，yiyusuzhushencengyishiwanchengbukenibangding。”】
liangzijiuchan？yishiyingshe？qiangrengongzhineng？zheixielingsuiqueyouwubizhenhandeciyu，rutongzhongchuiyibanqiaojizheluyangdexinzang。tasuiranzhishigeqianshihundeburuyideputongren，danbijinghuolewushinian，hulianwangshidaidexinxibaozhaduoshaoyerangtaduizheixiegainianyouxiemohuderenzhi。zheijueduibushitaneigeniandai，shenzhibushitahoulaijishiniansuonenglijiedekeji！
“ni…nidaodishishenmedongxi？”luyangzaixindiyongjinquanlisihouzhe，dantazhidao，zheishengyinwufachuandichuqu，zhinengzaizijideyishikongjianlihuidang。taganjuezijixianggejingshenfenliezhenghuanzhe，naozilipingkongduochuleyigeshengyin，yigezicheng“qizhi”deai。
【“guishu：‘guihangzhe’xieyibiaozhunpeizhi。”】
guihangzhexieyi？zheiyoushishenme？tingqilaixiangmougepangdajihuadeyibufen。biaozhunpeizhi？nandao……xiangtazheiyang“huigui”deren，buzhiyige？！zheigeniantourangluyangshunjiangandaoyizhenmaogusongran。
neigeshengyindunledun，sihushizaidengdailuyangxiaohuazheixiexinxi，ranhoujixuyitaneihengdingdeyusushuodao：
【“hexinrenwu：fuzhusuzhushengcun、shiyingdangqianhuanjing。”】
fuzhushengcun？shiyinghuanjing？tingqilaisihu……meiyoueyi？danluyangsihaobuganfangsongjingti。yigenengjiangrendeyishisonghuisanshiduonianqian，bingqiezichengqiangrengongzhinengdecunzai，zenmekenengjiandan？tapingshenmeyaobangzhuziji？daijiani？neigebinglengshengyinzaitigongxuanzeshitidaodeweizhi“daijia”youshishenme？
wushudeyiwenrutongxiongyongdechaoshui，shunjianjiangluyangyanmei。taganjuezijidedanaokuaiyaozhakaile，yibianyaojielilijiezheixiefeiyisuosidexinxi，yibianhaiyaopinmingweichizhebiaomiandepingjing，banyanhaoyigezhengzairenzhentingwulikedeshiqisuigaozhongsheng。
“陆扬！”
yigeyanlideshengyinturanzaierbianzhaxiang，jiangluyangconghunluandesixuzhongjingxing。tamengditaiqitou，zhijianwulilaoshizhangjianguozhengzhanzaijiangtaishang，zhouzhemeitoukanzheta，yanshenzhongdaizhemingxiandebuyue。
“wogangcaijiangdeziyouluotiyundongdetedian，nilaifushuyibian！”zhanglaoshideshengyinzaianjingdejiaoshilixiandegewaiqingxi。
wanle！luyangdexinmengdiyichen。tagangcaimannaozidoushineige“qizhi”，nalitingdaolaoshijiangleshenme？qianshitajiushigechengjizhongxiayoudexuesheng，wuligengshilaodanan，beilaoshidianmingtiwendabushanglaishijiachangbianfan，meicidouyinlaitongxuemendehongxiaohelaoshidepiping，rangtagengjiazibei。
nandaozhongshengdediyitian，jiuyaozhongyanguoqudejiongjingma？
zhouweitongxuedemuguangqishuashuadijujiaozaitashenshang，youhaoqi，youtongqing，yeyouxingzailehuo。tashenzhinengganjuedaoshenpangdesuxiaomanyeweiweiceguotou，toulailexunwendemuguang。
luyangdelianjiashunjianyouxiefatang，bushiyinweixiukui，ershiyinweiyizhongqiangliede、buyuanzaizhongfuguoqudequrugan。tazhanglezhangzui，houlongquexiangshibeishenmedongxiduzhule，fabuchurenheshengyin。danaoyipiankongbai，neixiegangganghaizainaohailipanxuandewuligongshi，cikexiaoshidewuyingwuzong。
jiuzaitazhunbeiyingzhetoupishuo“wobuzhidao”deshihou，neigebinglengdeshengyinzaicixiangqi，quedaizheyizhongburongzhiyideqingxi：
【“xinxitiqu：ziyouluotiyundong。dingyi：wutizhizaizhonglizuoyongxiacongjingzhikaishixialuodeyundong。tedian：1.chusuduv₀=0；2.jiasudua=g（hengding，fangxiangshuzhixiangxia）；3.yundongguijiweizhixian。xiangguantuilun：mosuduv=gt；weiyih=½gt²；v²=2gh。zhuyi：zaibiaozhunmoxingzhong，kongqizulihulvebuji。”】
yishunjian，guanyuziyouluotiyundongdesuoyouzhishidian，rutongshujuliuyibanqingxidizhuruletadedanao，tiaolifenming，luojiyanjin，bitazijikanshulijiedehaiyaotouche！
luyanglengzhule，zheishi……“qizhi”zaibangta？
“luyangtongxue？nitingdaowodewentilema？”zhanglaoshijiantabantianmeifanying，yuqigengjiabumanle，shouzhongdefenbizaijiangtaishangqiaoleqiao。
bunengzaiyouyule！luyangdingledingshen，shenxiyikouqi，yingzhequanbantongxuehelaoshidemuguang，huanhuanzhanqishen。taqingleqingsangzi，nulirangzijideshengyintingqilaipingwenyixie，ranhouanzhaonaohaizhong“qizhi”tigongdexinxi，kaishihuida：
“zhanglaoshi，ziyouluotiyundongshizhiwutizhizaizhonglizuoyongxia，congjingzhikaishixialuodeyundong。”tadeshengyinqichuhaiyouxieganse，dansuizhehuayudeliutang，zhujianbiandeqingxierzixin，“tadezhuyaotedianyousange：diyi，tadechusuduweiling；dier，tadejiasudushihengdingdezhonglijiasudug，fangxiangshuzhixiangxia；disan，tadeyundongguijishiyitiaozhixian。”
tadunledun，kandaozhanglaoshiyanzhongshanguoyisijingya，jixubuchongdao：“youcikeyituidaochujigezhongyaodegongshi，birumosududengyugt，xialuogaodudengyuerfenzhiyigtdepingfang，yijimosududepingfangdengyu2gh。dangran，zheixiedoushizaihulvekongqizulidelixiangqingkuangxiadejielun。”
教室里鸦雀无声。
suoyourendoujingyadikanzheluyang，fangfoburenshitayiyang。zheihaishineigepingshiwulikeshangzongshimimihuhu，beitiwenjiuzhizhiwuwudeluyangma？huidadebujinwanquanzhengque，erqietiaoliqingxi，shenzhihaibuchonglelixiangmoxingdetiaojian，zheijianzhi……buxiangtanengshuochulaidehua。
lianzhanglaoshiyelengzhule，tatuiletuibiliangshangdeheikuangyanjing，zixididaliangzheyanqianzheigexuesheng。jintiandeluyang，sihuzhendeyoudianbuyiyang。yanshenbuzaishiwangchangdeduoshanhemimang，ershidaizheyizhong……chenwen？shenzhihaiyouyisibuyichajuederuili。
“ng……huidadehenhao，henquanmian。”guolejimiaozhong，zhanglaoshicaidianlediantou，yuqihuanhelebushao，“kanlainiyuxidebucuo。zuoxiaba。qitatongxueyeyaoxiangluyangtongxuezheiyang，keqianzuohaoyuxi，ketangshangcainenggenshangsilu。”
luyangyiyanzuoxia，houbeiquejingchuleyicenglenghan。gangcaineiyike，taganjuezijixiangshizaizougangsi。xinghao……xinghaoyouzheige“qizhi”。suiranlailibuming，mudeweizhi，danzhishaozaigangcai，taqueshibangtajielewei。
tanengganjuedaozhouweitongxuetoulaideyiyangmuguang，youqishiqianpaidewanglei，zhengqiaoqiaohuiguotou，duitajimeinongyan，wushengdibilegedamuzhi。ershenpangdesuxiaoman，sihuyeduokanletaliangyan，neishuangqingchedeyanmoulidaizheyisihaoqihetanjiu。
luyangmeiyouhuiyingrenherendemuguang，tazhongxindixiatou，kanzhetankaidewulikeben，danxinsizaoyifeidaolejiuxiaoyunwai。
“qizhi……”tazaixinzhongmonianzhezheigemingzi，qingxufuzadaolejidian。zhenjing、jingti、kongju、yihuo，haiyouyisi……nanyiyizhidexingfenheqidai。
zheigeturanchuangrutashengmingdeshenmicunzai，jiujinghuijiangtadaixianghefang？shijiushudetianshi，haishiyindaotazouxianglingyigeshenyuandemogui？
buguanshishenme，taderensheng，congzheiyikeqi，zhudingwufazaipingjingle。tabixujinkuainongqingchuzheige“qizhi”deyiqie，tadenengli，tadexianzhi，tademude，yiji……neigexuanerweijuede“daijia”。
chuangwai，chanmingshengyizhengaoguoyizhen，xiariwuhoudeketangyijiuzaihuanmandijinxingzhe。danduiyuluyanglaishuo，tasuochudeshijie，yijingfashenglefantianfudidebianhua。tadelinghunshenchu，yigelaiziyaoyuanweilaidediyu，yijingdapolexianshidexukong，yushizheyichangbolanzhuangkuodefengbao，jijiangzaitazhongshengdeshiqisui，qiaoranyunniang。tajinjinwozhebi，zhijianbingliang，zhangxinqueqinchuleximidehanzhu。
wulike，haiyoumanzhangdeershifenzhongcaijieshu。erzheiershifenzhong，duiyucikedeluyanglaishuo，meiyimiaodourutongyigeshijibannanao。tabixuzaixiakezhiqian，zhenglihaozijideqingxu，bingzhunbeihaoyingjiezheigeshenmi“qizhi”kenengdailaidegengduochongji。