您所在的当前位置：高中物理试题 >

动量定理

> 在行车过程中，如果车距不够，刹车不及时，汽车将发生碰撞，车里的人可能受到伤害．为了尽可能地减轻碰撞引起的直接伤害，人们设计了如图所示安全带．假定乘客质量为70kg，汽车车速为108km/h，从踩下刹车到车完全停止需要的时间为5s，安全带对乘客的作用力大小约为（　　） A．400N B．600N C．800N D．1000N

问题：

发布时间：2024-09-08

在行车过程中，如果车距不够，刹车不及时，汽车将发生碰撞，车里的人可能受到伤害．为了尽可能地减轻碰撞引起的直接伤害，人们设计了如图所示安全带．假定乘客质量为70kg，汽车车速为108km/h，从踩下刹车到车完全停止需要的时间为5s，安全带对乘客的作用力大小约为（　　）

A．400N B．600N C．800N D．1000N

参考答案：

提问用户：Bs***9Om

可能感兴趣的题目：

1 某同学通过以下步骤测出了从一定高度落下的排球对地面的冲击力：将一张白纸铺在水平地面上，把排球在水里弄湿，然后让排球从规定的高度自由落下，并在白纸上留下球的水印．再将印有水印的白纸铺在台秤上，将球放在纸上的水印中心，缓慢地压球，使排球与纸接触部分逐渐发生形变直至刚好遮住水印，记下此时台秤的示数即为冲击力的最大值．下列物理学习或研究中用到的方法与该同学的方法相同的是______．（A）建立“合力与分力”的概念（B）建立“点电荷”的概念（C）建立“电场强度”的概念（D）建立“光子说”的理论．
2 铁块受热膨胀，是因为 A.铁的分子膨胀大 B.分子间的间隙增加 C.分子发生了扩散现象 D.分子运动的速度加大
3 — great fun we had ! — Yes, I will never forget it! A.What B.What a C.How D.How a
4 我国外流河绝大多数是注入 A.大西洋 B.太平洋 C.印度洋 D.北冰洋
5 一位农民说：“如果能卖到2000元一斤，我能在北京种出柑橘。”从这句话可看出农业生产归根结底取决于 A．国家的政策和措施 B．城市化发展的程度 C．工业化水平的高低 D．市场的需求
6 某无色透明溶液，加入金属铝反应放出H 2，试判断下列离子：Mg 2+、Cu 2+、Ba 2+、H +、Ag +、SO 4 2-、 HCO 3 -、OH -、NO 3 - 在下列两种情况中，可能大量存在于此溶液中的是：（1）当与Al反应后，生成Al 3+ 时，原溶液可能存在的离子有______________ ；（2）当与Al反应后，生成AlO 2 -时，原溶液可能存在的离子有______________ 。
7 已知在函数f（x） y= 3 sin πx R 图象上，相邻的一个最大值点与一个最小值点恰好在圆x 2+y 2=R 2上，则f（x）的最小正周期为（　　） A．1 B．2 C．3 D．4
8 下列关于S、Si、N、Cl等非金属元素化合物的说法正确的是（） A．SiO2是制造太阳能电池板的主要材料 B．NO、NO2是大气污染物，能在空气中稳定存在 C．漂白精的有效成分是Ca（ClO）2 D．Fe与S化合生成Fe2S3
9 某程序框图如图所示，该程序运行后输出的倒数第二个数是（　　） A． B． C． D．
10 阅读理解。 Computer programmer David Jones earns $35.000 a year designing new computer games, yet he cannot find a bank ready to let him have a credit card (信用卡). Instead he has been told to wait another two years until he is 18. The 16-year-old works for a small firm in Liverpool where the problem of most young people of his age is finding a job. David"s firm releases (推出) two new games for the fast growing computer market each month But David"s biggest headache is what to do with his money. Even though he earns a lot he cannot drive a car take out a mortgage (抵押贷款), or get credit cards. David got his job with the Liverpool-based company four months ago, a year after leaving school with six O-levels and working for a time in a computer shop "I got the job because the people who run the firm knew I had already written some programs" he said. David spends some of his money on records and clothes and gives his mother 50 pounds a week. But most of his spare time is spent working "Unfortunately, computing was not part of our studies at school" he said "But I had been studying it in books and magazines for four years in my spare time. I knew what I wanted to do and never considered staying on at school. Most people in this business are fairly young, anyway" David added:"I would like to earn a million and I suppose early retirement (退休) is a possibility. You never know when the market might disappear." 1. In what way is David different from people of his age? A. He often goes out with friends B. He lives with his mother C. He has a handsome income D. He graduated with six O-levels 2. What is one of the problems that David is facing now? A. He is too young to get a credit card B. He has no time to learn driving C. He has very little spare time D. He will soon lose his job 3. Why was David able to get the job in the company? A. He had done well in all his exams B. He had written some computer programs C. He was good at playing computer games D. He had learnt to use computers at school 4. Why did David decide to leave school and start working? A. He received lots of job offers B. He was eager to help his mother C. He lost interest in school studies D. He wanted to earn his own living