问题 填空题

质量相等的正方体木块和铁块都放在水平地面上,对地面压强较大的是______,用手把它们都放于水面下,松开手待它们静止后,受浮力较大的是______.

答案

(1)因为木块和铁块质量相等,所以重力相等,即对水平地面的压力相等,铁块的密度大于木块的密度,根据V=

m
ρ
可知,铁块的体积小于木块的体积,又因为都是正方体,所以铁块的边长小于木块的边长,那么铁块的底面积小于木块的底面积,根据P=
F
S
可知,对地面压强较大的是铁块.

(2)因为木块的密度小于水的密度,所以木块最后要漂浮在水面,木块受到的浮力等于木块的重力,铁块的密度大于水的密度,铁块下沉,铁块受到的浮力小于铁块的重力,又因为木块和铁块的重力相等,所以木块受到的浮力大于铁块受到的浮力.

故答案为:铁块、木块.

阅读理解

阅读理解。

     Monday…oh, I don't like Monday because I'll have to go back to school again after the weekend.

Tuesday is not so bad. I usually play tennis with my friends after school. On Wednesday evening I

don't go out. I stay at home and do my homework. I like Thursday because the next day is Friday.

I always go out on Friday-maybe to the cinema. I love the weekend. On Saturdays I get up late,

and I sometimes go to the shops in the afternoon. In the evening we go to a club. Then on Sundays

I go to my friend's house or she comes to mine. I usually visit my grandmother for an hour in the

afternoon. Then the weekend is over and it's Monday…and I feel bad again!

1. I don't like Monday because            .

A. Monday is the first day of a week      

B. I just spend a happy weekend

C. Monday is the first school day of a week  

D. I will have many lessons on Monday

2. Tuesday is not so bad because            .

A. I can play tennis with my friends  

B. I have no homework to do

C. I have a P.E. class  

D. I'm free

3. I can go to the cinema on            .

A. Monday  

B. Tuesday  

C. Wednesday  

D. Friday

4. Which one is true?

A. I get up late on Monday.  

B. I visit my grandmother on Saturday.

C. I play tennis on Sunday.        

D. I do some shopping at weekends.

5. From the text, we know that the writer            .

A. doesn't like school        

B. likes to stay at home

C. only likes Friday  

D. only likes Saturday

填空题