问题
单项选择题
重力为W的人乘电梯上升时,当电梯加速上升、匀速上升及减速上升时,人对地板的压力分别为p1、p2、p3,它们之间大小的关系为()。
A.p1=p2=p3
B.p1>p2>p3
C.p1<p2<p3
D.p1<p3>p2
答案
参考答案:B
解析:
应用牛顿第二定律。
重力为W的人乘电梯上升时,当电梯加速上升、匀速上升及减速上升时,人对地板的压力分别为p1、p2、p3,它们之间大小的关系为()。
A.p1=p2=p3
B.p1>p2>p3
C.p1<p2<p3
D.p1<p3>p2
参考答案:B
解析:
应用牛顿第二定律。
从方框内选出单词,用其适当形式填空。每空格限填一词,每词限用一次。 | |
2. Bill likes Chinese food very much, but he doesn't like ________ food at all. 3. Nancy's daughter is ________ at seven every morning. 4. How many _________ can you see in the picture? 5. It's much better for wild animals to live in a _________ environment than in a zoo. 6. I have never been to an __________ park before. |