某同学乖船由甲地顺流而下到乙地，然后又逆流而上到丙地，共用3埘，若水流速为2㎞/h，船在静水中的速 某学生乘船由甲地顺流而下到乙地,然后又逆流而上到丙地,共用3...
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绛旓細璁撅細鑸瑰湪闈欐按涓殑閫熷害涓簐锛岀敳涔欑殑璺濈涓篨锛岀敳涓欑殑璺濈涓2/3脳X x梅(V+a)脳3=(X+2/3脳X)梅锛圴-a锛夊緱鍑猴紝V=7/2a
绛旓細璁剧敳涔欎袱鍦扮浉璺漍鍗冪背銆傚垯涔欎笝鐩歌窛X-10鍗冪背銆傦紙X-10锛/锛8-2锛+X/锛8+2锛=3 5X-50+3X=90 8X=140 X=17.5鍗冪背銆傜敳涔欎袱鍦扮浉璺17.5鍗冪背銆
绛旓細鏌愪汉涔樿埞鐢辩敳鍦伴『娴佽屼笅鍒颁箼鍦鐒跺悗閫嗘祦鑰屼笂鍒颁笝鍦板叡鐢3灏忔椂鑻ユ按娴侀熷害涓2鍗冪背/鏃惰埞鍦ㄩ潤姘翠腑鐨勯熷害涓8鍗冪背/鏃朵笖鐢蹭笝涓ゅ湴璺▼涓2鍗冪背姹傜敳涔欎袱鍦拌矾绋... 鏌愪汉涔樿埞鐢辩敳鍦伴『娴佽屼笅鍒颁箼鍦扮劧鍚庨嗘祦鑰屼笂鍒颁笝鍦板叡鐢3灏忔椂鑻ユ按娴侀熷害涓2鍗冪背/鏃惰埞鍦ㄩ潤姘翠腑鐨勯熷害涓8鍗冪背/鏃朵笖鐢蹭笝涓ゅ湴璺▼涓2鍗冪背姹傜敳涔欎袱鍦拌矾绋 灞曞紑 ...
绛旓細瑙ｏ細璁 鐢蹭箼涓ゅ湴鐨勮埅绋嬩负 x 鍗冪背锛鑸椤烘按閫熷害涓 7.5+2.5 = 10 (鍗冪背/灏忔椂)锛岃埞閫嗘按閫熷害涓 7.5 - 2.5 = 5 (鍗冪背/灏忔椂)鍒欐湁锛(x/10 + (x-10)/5 = 7 瑙ｅ緱锛 x = 30 鍗筹細鐢蹭箼涓ゅ湴鐨勮埅绋嬩负 30 鍗冪背
绛旓細椤烘祦鑰屼笅鐨勭敤鏃讹細6梅(9+3)=0.5(灏忔椂)閫嗘祦鑰屼笂鐨勭敤鏃讹細6-0.5=5.5(灏忔椂)閫嗘祦鑰屼笂鐨勯熷害锛9-3=6(鍗冪背/灏忔椂)鈭撮嗘祦鑰屼笂鐨勮窛绂伙細6x5.5=33(鍗冪背) 涔欎笝涓ゅ湴鐨勮窛绂绘槸33鍗冪背 鐢蹭箼涓ゅ湴鐨勮窛绂绘槸=涔欎笝涓ゅ湴鐨勮窛绂 - 鐢蹭箼涓ゅ湴鐨勮窛绂=33-6=27鍗冪背銆俿/v=9 (468+s)/v=35 瑙ｏ細v=s/9锛 ...
绛旓細1800
绛旓細12.5
绛旓細2鍗冪背涔3灏忔椂=6鍗冪背
绛旓細璁剧敳涔欎袱鍦扮殑璺▼涓簊.a.鍋囪涓欏湪鐢鐨勪笂娓革紝鍒欐湁锛歴/(7.5+2.5)+(10+s)/(7.5-2.5)=7 s=50/3 b.鍋囪涓欏湪鐢茬殑涓嬫父锛屽垯鏈夛細s/(7.5+2.5)+(10-s)/(7.5-2-5)=7 s鏃犺В 缁间笂鎵杩帮細s=50/3
绛旓細宸茬煡鑸瑰湪闈欐按涓殑閫熷害涓5鍗冪背姣忓皬鏃讹紝姘存祦鐨勯熷害涓3鍗冪背姣忓皬鏃讹紝鏌愪汉涔樿埞鐢辩敳鍦伴『娴佽屼笅鍒颁箼鍦锛岀劧鍚庡張閫嗘祦鑰屼笂鍒颁笝鍦帮紝鍏变箻鑸5灏忔椂锛岃嫢鐢蹭笝涓ゅ湴鐩歌窛5鍗冪背锛屾眰鍔犱竴涓ゅ湴闂寸殑璺濈銆傝鐢蹭箼璺濈鏄疿 (1)涓欏湪鐢蹭箼涔嬮棿锛歑/锛5+3锛+锛圶-5锛/锛5-3锛=5 X=12 锛2锛変笝鍦ㄧ敳鐨勪笂娓革細X/锛5+3锛+锛...
