奥运会期间在 鸟巢 与 水立方 的志愿者人数比为8；7,如果从鸟巢调出1/4的志愿者到水立方,那么 鸟巢 将比 水立方

During the Olympic flame burning in the main venue,that is the Olympic torch,which symbolizes light,unity,friendship,peace and justice.Torch originated in the ancient Greek myths and legends.According to Greek mythology,the Titan Prometheus for the rescue of destitute human beings,Aegis longer Department stole fire to the sun god Apollo to bring human,and never recovered after the fire to the world.Aegis had,in 2008 started prior to his worship.So the ancient Olympic Games to be held a grand opening ceremony of the ignition and combustion admission by the priest from the altar of the Olympic flame.All athletes together to torch run,the first three athletes will hold high the torch of visitor arrivals to Greece Chuanyu stop all war began quadrennial Olympic Games.Resumption of the modern Olympic movement,Pierre de Coubertin,the 1912 Olympic torch lit proposal lit the Olympic torch to start the 1928 ceremony.Since 1936,the Olympic torch began Olympia,Greece,the homeland of the Olympic Games torch lit.The torch will then spread to the host country relay and the opening ceremony of the Olympic Games when entering the venue,General famous athletes standing by the host torch blazing torch lit until the closing until extinguished.Winter Olympics began in 1952 torch lit.

设鸟巢人为8X,水立方为7X,从鸟巢调出四分之一到水立方即；鸟巢减少2X变成6X,水立方增加2X成9X.这样9x-6x=150得X=50,即鸟巢为400,水立方为350

解题思路：

(1)分析图线可知：电动车由静止开始做匀速直线运动，达到额定功率后，做牵引力逐渐减小的变加速直线运动，达到最大速度后做匀速直线运动。当最大速度时，牵引力为，故恒定阻力额定功率

(2)匀加速运动的末速度代入数据解得v=3m/s

匀加速运动的加速度代入数据解得

电动车在速度达到3m/s之前，一直做匀加速直线运动，故所求时间为

将代入上式解得t=1s

(3)在匀加速阶段有：

到达B点的位移为：

从B点到达最大速度过程中，由动能定理得：

故总的位移为：

（1）6kw   （2）t=1s    (3)26.25m


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