您所在的当前位置：高中物理试题 >

动量定理

> 质量为m的钢球自高处落下，以速率v 1碰地，竖直向上弹回，碰撞时间极短，离地的速率为v 2。在碰撞过程中，地面对钢球冲量的方向和大小为（） A．向下，m(v1-v2) B．向下，m(v1+v2) C．向上，m(v1-v2) D．向上，m(v1+v2)

问题：

发布时间：2020-03-13

质量为m的钢球自高处落下，以速率v ₁碰地，竖直向上弹回，碰撞时间极短，离地的速率为v ₂。在碰撞过程中，地面对钢球冲量的方向和大小为（）

A．向下，m(v₁-v₂) B．向下，m(v₁+v₂)

C．向上，m(v₁-v₂) D．向上，m(v₁+v₂)

参考答案：

提问用户：m7***sPK

可能感兴趣的题目：

1 不计重力的带电粒子在足够大的匀强电场中从A点静止释放，经过时间t，通过的路程为s，若此时突然使场强大小不变而方向相反，则带电粒子以后的运动情况是( ) A．立即反向运动 B．经过3t时间回到A点 C．经过(+1)t时间回到A点 D．从释放到回到A点时，总路程为4s
2 关于参照物以下说法正确的是 A.乘客看路旁的大树在向后退，是以大树作为参照物的 B.行驶的火车中，乘客说司机静止，是以路面作为参照物的 C.游客在花果山上，看到水帘洞的水飞流而下，是以洞口作为参照物的 D.说通信卫星静止在赤道上空，是以太阳作为参照物的
3 下图是“运用某种地理信息技术(GIS)来选址的工作流程图”。采用图示流程进行选址的设施可能是 A．大型油气储备库 B．核废料储存场 C．城市垃圾处理场 D．地下水天然补给区
4 已知角α的终边经过点P（-4a，3a）（a≠0），则2sinα+cosα的值为______．
5 I’m terribly sorry to turn you down this time, but I promise I will ______ to you next time. A．pick it up B．make it up C．turn it up D．set it up
6 ____ you may have, you should gather your courage to face the challenge., [ ] A. However a serious problem B. What a serious problem C. However serious a problem D. What serious a problem
7 阅读理解。 On May 23,1989, Stefania Follini came out from a cave at Carlsbad,New Mexico. She hadn"t seen the sun for eighteen and a half weeks. Stefania was in a research program,and the scientists in the program were studying body rhythms (节奏) . In this experiment Stefania had spent 130 days in a cave, 30 feet in depth. During her time in the cave,Stefania had been completely alone except for two white mice. Her living place had been very comfortable,but there had been nothing to tell her the time. She"d had no clock or watches,no television or radio. There had been no natural light and the temperature had always been kept at 21℃. The results were very interesting. Stefania had been in the cave for over four months,but she thought she had been there for only two. Her body clock had changed. She hadn"t kept to a 24-hour day. She had stayed awake for 20-25 hours and then had slept for 10 hours. She had eaten fewer meals and had lost 17 lbs in weight as a result ! She had also become rather depressed (抑郁) . How had she spent her time in the cave? As part of the experiment she"d done some physical and mental tests.She"d recorded her daily activities and the results of the tests on a computer. This computer had been specially programmed for the project. Whenever she was free, she"d played cards,read books and listened to music. She"d also learned French from tapes. The experiment showed that our body clocks are affected by light and temperature,for example,the pattem of day and night makes us wake up and go to sleep. However,people are affected in different ways. Some people wake up naturally at 5:00 am,but others don"t start to wake up till 9:00 0r 10:00 am. This affects the whole daily rhythm. As a result,the early risers are at their best in the late moming. The late risers,on the other hand,are tired during the day and only come to life in the aftemoon or evening ! 1. Stefania stayed in the cave for a long time because___. A. she was asked to do research on mice B. she wanted to experience loneliness C. she was the subject of a study D. she needed to record her life 2. What is a cause for the change of Stefania"s body clock? A. Eating fewer meals. B. Having more hours of sleep. C. Lacking physical exercise. D. Getting no natural light. 3. Where doos the text probably come from? A. A novel. B. A news story. C. A pet magazine. D. A travel guide.
8 (15分)如图所示，质量为m的木板静止地放在光滑水平面上，质量为2m、可视为质点的木块以水平速度v 0从左端滑上木板，木块与木板间的动摩擦因数为μ，木板足够长。 ⑴求木块和木板的加速度大小； ⑵求木块和木板速度相等所经历的时间及此时木块相对于木板的位移； ⑶若木板不是足够长，要使木块不从木板上滑落，求木板的最小长度。
9 如图，图中的程序输出的结果是（　　） A．5 B．15 C．10 D．20
10 下图为“我国西南某区域不同地理要素图层”。读图，回答下列问题。小题1:该区域 A．①地以落叶阔叶林为主 B．②地适宜种植小麦 C．高级住宅区集中在③地 D．钢铁厂布局在④地小题2:据图推断 A．居民点向东南方扩展 B．森林面积扩大，酸雨危害减弱 C．湿地面积减少，地下水源增加 D．GIS可应用于道路规划

质量为m的钢球自高处落下，以速率v 1碰地，竖直向上弹回，碰撞时间极短，离地的速率为v 2。在碰撞过程中，地面对钢球冲量的方向和大小为（ ） A．向下，m(v1-v2) B．向下，m(v1+v2) C．向上，m(v1-v2) D．向上，m(v1+v2)

可能感兴趣的题目：