问题 填空题

烧杯内盛有足量的水,把一质量为1kg铝块用细线系在弹簧测力计下浸在水中,静止时测力计的示数为7.5N.则铝块在水中受到的浮力为______N,方向为______.(g=10N/kg)

答案

∵G=mg=1kg×10N/kg=10N,

∴物体在水中所受浮力:

F=G-F=10N-7.5N=2.5N.

浮力的方向是竖直向上.

故答案为:2.5;竖直向上.

完形填空

       Mary loved small animals. One morning while she was walking in the forest, she found           weak birds in the grass. She took them home and put them in a small cage (笼子). She cared them with love and the birds both grew      . They thanked her   a wonderful song every morning.

But something happened one day. Mary left the door of the      open. The larger bird flew from the cage. She thought that it would       . As it flew close, she grasped (紧抓) it. She was very excited to catch it.        she felt strange. She opened her hand and looked sadly at the       bird. Her great love had killed the bird!

The other bird was moving back and forth (来回) in the cage. Mary could       its great need for freedom (自由). It wanted to fly into the clear and blue             . At once, Mary took the bird      the cage and let it fly away. The bird circled once, twice, three times…

小题1:A. some              B. several                C. two

小题2:A. small             B. strong                 C. thin

小题3:A. with                 B. for                C. about

小题4:A. house             B. room             C. cage

小题5:A. come back       B. die out                C. fly away

小题6:A. Suddenly             B. Usually           C. Easily

小题7:A. living          B. interesting            C. dead

小题8:A. take                 B. feel               C. say

小题9:A. river                B. trees              C. sky

小题10:A. out of           B. out from           C. away of

填空题