一长方体铁块按图所示，从下表面与液面刚刚接触时下放至图中虚线_爱下问搜题

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问题选择题

一长方体铁块按图所示，从下表面与液面刚刚接触时下放至图中虚线位置。能大致反映铁块下降过程中所受浮力的大小F_浮与铁块下表面浸入液体深度h_深关系的图像是

答案

答案：B

当物体从开始浸入水中到完全浸入水中即浸没的过程中，物体排开液体的体积在逐渐变大，液体密度不变，因为F_浮=ρ_液V_排g，所以物体受到的浮力变大；而当物体浸没以后，再向水中下沉的时候，物体排开液体的体积不再发生变化，所以物体受到的浮力不变．由此可知物体受到的浮力先变大后不变．

故选B

阅读理解

阅读理解。

Holiday News
Vacancies (空位) now and in the school holidays at a country hotel in
Devon. This comfortable, friendly home-from-home lies near the beautiful
quiet countryside, but just a drive away from the sea. The food is simple but good. Children and pets are welcome. Reduced prices for low season.

                                       The Snowdonia Center
     The Snowdonia Center for young mountain climbers has a mountain
lesson. The beginners' costs are ￡57 for a week, including food and rooms. Equipment is included except walking shoes, which can be hired at a low
cost.
     You must be in good health and prepared to go through a period of
body exercises. This could be the beginning of a lifetime of lifetime of mountain
climbing adventure.

                             The World Sea Trip of a Lifetime
     Our World Sea Trip of 2008 will be unlike any holiday you have ever
been on before. Instead of one hotel after another, with all its packing and
unpacking waiting and traveling, you just go to bed in one country and
wake up in another.
     On board the ship, you will be well taken care of. Every meal will be
first-class and every cabin like your home.
     During the trip, you can rest on deck(甲板), enjoy yourself in the
games rooms and in the evening dance to our musical team and watch our
wonderful play.
     You will visit all the places most people only dream about - from
Acapulco and Hawaii to Tokyo and Hong Kong.
     For a few thousand pounds, all you've ever hoped for can be yours.

1. What can you do if you like to go on holidays with pets?

A. Choose the holiday in Devon.
B. Go to the Snowdonia Centre.
C Join the World Sea Trip of 2008.
D. Visit Acapulco and Hawaii.

2. In what way is the Snowdonia Centre different from the other two holidays?

A. It provides chances of family gatherings.
B. It provides customers with good food.
C. It offers a sport lesson.
D. It offers comfortable room.

3. What is special about the World Sea Trip of 2008?

A. You can have free meals on deck every day.
B. You can sleep on a ship and tour many places.
C. You will have chances to watch and act in a play.
D. You have to do your own packing and unpacking.

4. At the Snowdonia Centre, the beginners' costs of ￡57 do not cover _____.

A. food
B. rooms
C. body exercises
D. walking shoes

问答题简答题

圆角半径确定时要注意什么？