题干

如图a、b、c三个实心小球,其中a与b质量相等,b与c体积相同;将三个小球放入水中静止不动时,a球漂浮、b球悬浮、c球沉底.则下列判断中正确的是(  )


A:它们在水中的体积关系是:Va<Vb=Vc

B:它们的重力关系是Ga=Gb>Gc

C:它们的密度关系是:ρa<ρb<ρc

D:它们所受的浮力关系是:Fa=Fb=Fc

上一题 下一题 0.0难度 选择题 更新时间:2011-12-20 11:41:17

答案(点此获取答案解析)

C,D

同类题2

阅读下列短文,从每题所给的四个选项 A、B、C、D中选出最佳选项。

C

    There are over 800 boarding schools in the UK with students from home and foreign countries. Boarding schools started hundreds of years ago in the country. But the earliest boarding schools were set up for white, rich boys only. Now both boys and girls can go to boarding schools from the age of 7 to 18.

    What to do?

    In the UK, boarding schools have three terms in a school year, with about 13 weeks in each term. Students study and live together. They can't go outside if they are not allowed to. In some schools, each student has his or her subject plan. Besides the usual classrooms and laboratories, the boarding schools have lots of other facilities for their students, including music rooms, boats, swimming pools, cinemas and theatres. Most boarding schools have a "light-out" time. So when it's time to go to bed, all the lights in the bedrooms are turned off. There are house-masters to take care of students all the time, especially after school hours.

    What to wear?

Nearly all students at boarding schools wear a school uniform. Boys usually wear a shirt and a tie, and girls wear a white blouse, sometimes also a tie and a skirt. As students get older, the rules become less strict.

    ____________?

    In the UK, boarding schools provide students with delicious food. They can choose to have a full English breakfast or simply bread. They can also choose between a meal with no meat and another meal at lunch and dinner. And there is always self-service for salad (沙拉), other side dishes and a dessert. Students can also make themselves something to eat at any time in a kitchen, or drink tea or have a snack between meals.