问题 计算题

水平桌面上放置一轻质圆筒,筒内装有0.2米深的某液体,如图(a)所示。弹簧测力计悬挂底面积为10-22、高为0.1米的圆柱体,从液面逐渐浸入直到浸没,弹簧测力计示数F与圆柱体浸入液体深度h的关系如图(b)所示。圆筒的厚度忽略不计,筒内液体没有溢出,圆柱体不碰到筒底。

①若F1=9.8牛,F2=1.96牛,求圆柱体浸没时所受浮力F;筒内液体的密度ρ

②圆柱体未浸入时筒底受到的液体压强p

③若轻质圆筒的底面积为2S,筒内液体深度为2h,液体密度为ρ,圆柱体底面积为S、高为h,求圆柱体浸没时,圆筒对桌面的压强p。(用字母表示)

答案

①800千克/米3②1568帕③2.5ρgh

题目分析:①F= F1-F 2=9.8牛-1.96牛=7.84牛 ρ=F/Vg =7.84牛/(10-33×9.8牛/千克)=800千克/米3

②pgh=0.8×103千克/米3×9.8牛/千克×0.2米=1568帕

③p=F/S =(ρ2S×2hg+ρShg)/2S =2.5ρgh                   

单项选择题
阅读理解

     The Internationa1 Space Station allows astronauts to live in space for extended amounts of time,

enabling them to explore the outside universe al1d conduct many experiments. However, nothing like that

exists for our oceans, and thanks to the high water pressure, ocean researchers are able to explore what

lies undersea for very short periods of time.

     They are therefore never able to fully explore the deep inside areas of our oceans. However, if

French architect Jacques Rougerie has his way, that will change soon.

     Jacques has designed a ship that will allow researchers to spend a long period of time observing the

sea life and conducting experiments. The huge l67ft. ship, named' SeaOrbiter', consists of two areas-one

above the water where the scientists and crew will live, and a lower pressurized deck (甲板), where

scientists will be able to spend as much time as they wish. Since it is powered by sea currents and wind,

he expects it to drift (漂流) along the oceans slowly, taking about two years to circumvent the globe.

     Jacques will make their life as comfortable as possible in the ship. Besides being equipped with the

latest sailing tools and communication equipment, the ship will also have a gym, a television and a DVD

player! And these guys will not be eating freeze-dried food like astronauts. Instead, Jacques, an

accomplished chef, plans on cooking them delicious meals every day.

     The biggest problem to this giant ship is the cost, which is expected to be over $500 million-per ship!

However, Jacques, who strongly believes that the secrets of our oceans may be the key to solving global

warming and a vital supply for food and medicine in the future, is confident he will be able to convince

governments all over the world to help out, and expects to start construction on not one, but four or five

of these amazing ships soon!

1. Why can't ocean researchers explore the deep oceans for a long time?

A. Because they can't stand the high water pressure.

B. Because it's too cold in deep ocean.

C. Because time for experiments is too limited.

D. Because it's dangerous to observe the sea life.

2. The underlined word "circumvent" probably means      .

A. fly away    

B. get around    

C. travel through    

D. move into

3. From the fourth paragraph we can learn that      .

A. Jacques intends to design the ship mainly for sightseeing and traveling

B. living a comfortable life helps to do the ocean research quickly

C. it's much more expensive to eat freeze-dried food

D. researchers on Jacques'ship will live more comfortably than astronauts

4. In Jacques' opinion, which of the following is not the purpose of the undersea research?

A. To find supply for food in the future.

B. To find supply for medicine in the future.

C. To draw governments' attention to the construction of the ship.

D. To solve the global warming.

5. Which of the fol1owing would be the best title for the text?

A. Sea Orbite-the ship of the future  

B. A new way to explore the deep oceans

C. A great architect-Jacques Rougerie 

D. Travel around the globe in Sea Orbiter