皮皮学，免费搜题
登录
logo - 刷刷题
搜题
【简答题】
2009年10月9日，美国两航天器先后撞击月球．如图甲所示，“半人”火箭撞月时，在月球上击起一点六公里高的尘埃，其中含有约二十五加仑的水．结果显示，月球上存在水，引起了人们的广泛兴趣． （1）科技人员是通过电磁波来向两航天器传递控制信号的，若该电磁波的频率为750 kHz，其波长是______m．月球离地球平均距离3.84×10 5 km，则航天器即将撞月前，发出的信号约需______s才能传到地球．（电磁波在真空中的速度c=3×10 8 m/s） （2）航天器在准备撞月减速过程中其动能______  （增加/不变/减少）；它与月球的碰撞会产生大火球，此过程中能量的转化情况是______． （3）在网上看到图甲的航天器撞月图片之后，联想到在体育比赛中撑杆跳高运动员要落在厚厚的海绵垫上（图乙）．根据以上现象，提出一个问题：一个物体撞击其他物体时，撞击力的大小是否与相互作用的时间有关？他猜想：可能与相互作用的时间有关． 根据自己的猜想，设计了如下的实验方案：在两个相同的玻璃槽中不同厚度的面粉，从相同的______，先后由静止释放同一只鸡蛋，落在面粉厚度大的槽中，留下较深的坑，鸡蛋完好无损；落在面粉厚度较小的槽中，鸡蛋破裂．在这里，是通过比较______看出撞击时间的长短．由此，你得出的结论是______．
手机使用
分享
复制链接
新浪微博
分享QQ
微信扫一扫
微信内点击右上角“…”即可分享
反馈
参考答案：
举一反三
【简答题】在曲柄摇杆机构中，若以摇杆为主动件，最小传动角发生的位置在曲柄与　　　　　　　共线位置。
查看完整题目与答案
【判断题】曲柄摇杆机构中最小传动角的位置可能发生在曲柄与连杆共线的两位置之一
A.
正确
B.
错误
查看完整题目与答案
【单选题】Which of the following is NOT TRUE?
A.
We have atoms all around us.
B.
All atoms are moving.
C.
There are millions of atoms in only one grain of salt.
D.
When heated, an object will hold together and give its shape.
查看完整题目与答案
【单选题】Five other planets ______.
A.
always appear near the path of the sun
B.
are moving in a way more complicated than the earth does
C.
aren't moving around the sun as independently as the earth does
D.
are moving around the san at the same speed as the earth does
查看完整题目与答案
【单选题】All the other five planets______.
A.
always appear near the path of the sun
B.
are moving in a way more complicated than the earth does
C.
aren’t moving around the sun as independently as the earth does
D.
are moving around the sun at the same speed as the earth does
查看完整题目与答案
【多选题】第二节 七选五(共 5 题,每题 2 分,共 10 分) 1. 根据短文内容 , 从短文后的选项中选出能填入空白处的最佳选项 , 选项中有两项为多余选项。 Self-care activities can help you cope with stress and improve overall well-being. 1 ______. Normally, a good deal of prac...
A.
Eat healthy foods
B.
Have your meal regularly
C.
Practicing self-care is especially important
D.
Schedule time-off from your responsibilities
E.
Schedule regular appointments with your doctor
F.
However, people are practicing self-care everyday
G.
Choose activities that are fun and interesting for you
查看完整题目与答案
【简答题】在曲柄摇杆机构中，若以摇杆为主动件，最小传动角发生的位置在　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　位置。
查看完整题目与答案
【简答题】在曲柄摇杆机构中,最小传动角发生的位置在 。
查看完整题目与答案
【判断题】曲柄摇杆机构中最小传动角的位置可能发生在曲柄与连杆共线的两位置之一。
A.
正确
B.
错误
查看完整题目与答案
【单选题】A He doesn't want to be his own boss. B. He hates getting outside. C. He dislikes moving around. D. He doesn't like to stay in the office.
A.
A He doesn't want to be his own boss.
B.
He hates getting outside.
C.
He dislikes moving around.
D.
He doesn't like to stay in the office.
查看完整题目与答案
相关题目：
【简答题】在曲柄摇杆机构中，若以摇杆为主动件，最小传动角发生的位置在曲柄与　　　　　　　共线位置。
查看完整题目与答案
【判断题】曲柄摇杆机构中最小传动角的位置可能发生在曲柄与连杆共线的两位置之一
A.
正确
B.
错误
查看完整题目与答案
【单选题】Which of the following is NOT TRUE?
A.
We have atoms all around us.
B.
All atoms are moving.
C.
There are millions of atoms in only one grain of salt.
D.
When heated, an object will hold together and give its shape.
查看完整题目与答案
【单选题】Five other planets ______.
A.
always appear near the path of the sun
B.
are moving in a way more complicated than the earth does
C.
aren't moving around the sun as independently as the earth does
D.
are moving around the san at the same speed as the earth does
查看完整题目与答案
【单选题】All the other five planets______.
A.
always appear near the path of the sun
B.
are moving in a way more complicated than the earth does
C.
aren’t moving around the sun as independently as the earth does
D.
are moving around the sun at the same speed as the earth does
查看完整题目与答案
【多选题】第二节 七选五(共 5 题,每题 2 分,共 10 分) 1. 根据短文内容 , 从短文后的选项中选出能填入空白处的最佳选项 , 选项中有两项为多余选项。 Self-care activities can help you cope with stress and improve overall well-being. 1 ______. Normally, a good deal of prac...
A.
Eat healthy foods
B.
Have your meal regularly
C.
Practicing self-care is especially important
D.
Schedule time-off from your responsibilities
E.
Schedule regular appointments with your doctor
F.
However, people are practicing self-care everyday
G.
Choose activities that are fun and interesting for you
查看完整题目与答案
【简答题】在曲柄摇杆机构中，若以摇杆为主动件，最小传动角发生的位置在　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　位置。
查看完整题目与答案
【简答题】在曲柄摇杆机构中,最小传动角发生的位置在 。
查看完整题目与答案
【判断题】曲柄摇杆机构中最小传动角的位置可能发生在曲柄与连杆共线的两位置之一。
A.
正确
B.
错误
查看完整题目与答案
【单选题】A He doesn't want to be his own boss. B. He hates getting outside. C. He dislikes moving around. D. He doesn't like to stay in the office.
A.
A He doesn't want to be his own boss.
B.
He hates getting outside.
C.
He dislikes moving around.
D.
He doesn't like to stay in the office.
查看完整题目与答案
参考解析：
知识点：
题目纠错 0
发布
创建自己的小题库 - 刷刷题