质量相等的两个实心小球甲和乙，已知它们的密度之比是ρ甲：ρ乙=2：3．现将甲、乙两球放入盛有足够多水的烧杯中，当甲、乙两球静止时，水对两球的浮力F甲：F乙=6：5，两球的密度分别是______和______．
经分析得出甲球漂浮，乙球下沉，因为两球质量相等，密度之比是ρ甲：ρ乙=2：3，体积之比为V甲：V乙=3：2，
F甲：F乙=ρ甲V甲g：ρ水V乙g=ρ甲V甲：ρ水V乙=6：5，
所以ρ甲=
=6ρ水V乙 5V甲
=8003kg/m3，又因为ρ甲：ρ乙=2：3，6×1000kg/m3×2 5×3
所以ρ乙=12003kg/m3．
故答案为8003kg/m3；12003kg/m3．
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| The ancient Olympic Games were religious (宗教的) activities. 1 held the first Olympic Games in the sixth century B. C. At that time, men could be 2 the races. Women had no 3 to take part in the Olympic Games 4 1912. The modern Olympics started in Athens in 1896. Since then we hold the Olympic Games every four years. The IOC (国际奥委会) 5 athletes. So they all have the same chance 6 . Winning at the Olympics is a great honor. Those 7 win at the Olympics are the best in the world." Faster, higher, 8 "is the slogan (口号) of the Olympics. China has won many gold medals 9 Xu Haifeng got China's first Olympic medal. Many excellent players, such as Liu Guoliang and Guo Jingjing, have 10 good examples to us. When Liu Xiang passed the finishing line, all the Chinese people jumped up and down, 11 . Everyone in China felt 12 and proud. As we know, China 13 the host country to hold the 29th Olympic Games in the year 2008. The five Fuwa images (福娃) have been chosen as the official mascots (吉祥物) of the Olympics. 14 athletes will come to Beijing to compete (竞争) for medals. We hope our country can hold the Olympics 15 . We also hope all the athletes can work hard and set more world records. | |||
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