题目内容
钓鱼岛(The Diaoyu Islands)自古就是我国固有领土，又称钓鱼台、钓鱼台群岛、钓鱼台列岛，位置在距温州市约356km、福州市约385 km、基隆市约190 km。若我国某海监船为维护我国对钓鱼岛主权，从温州出发去钓鱼岛巡航，到达钓鱼岛时航行了480 km。则下列说法中不正确的是
| A．该海监船位移是480 km，路程356km |
| B．该海监船位移是356 km，路程480 km |
| C．该海监船在海上航行时，确定其位置时可以将该海监船看成质点 |
| D．若知道此次航行时间可求出此次航行的近似平均速度 |
A
解析试题分析：位移表示由初位置指向末位置的有向线段，路程表示实际运动轨迹的长度，故路程大于等于位移大小，所以该海监船位移是356 km，路程480 km，A错误，B正确，
该海监船在海上航行时，确定其位置时其大小和形状可以忽略故能看做质点，C正确，
平均速度等于位移与时间的比值，故给出时间即可求出平均速度，D正确，
故选A
考点：考查了位移，路程，质点，平均速度等概念
点评：平均速度等于位移与时间的比值，平均速率等于路程与时间的比值，路程大于等于位移大小，当做单向直线运动时，位移大小等于路程
阅读快车系列答案Dear Chicken Soup for the Teenage Soul,
Most people don’t really know what pressures a typical teenager has to go through. Sure, our parents and grandparents were once teens, but things are so different now. It has never been to tougher (严格)to a teenager.
It had never been more important to be in the “right group” or to have the “right brand” of shoes. And those are the easy things to deal with. We also face problems with family, friends, relationships and school pressures.
When it gets to be too much, I turn to my friends. One friend I could not live without is Chicken Soup for the Teenage Soul. Your books have been so inspiring to me and have helped me to deal with and understand the problems I go through.
For example, I went through a confusing time with my friends when we got to junior high. I had known these friends since kindergarten, and when we began junior high it seemed like some of them began to change. We started hanging out with different groups, and we slowly grew so far apart that it seemed as if we had never been friends. I felt confused and hurt.
Sometime during this period I read the story Friends Forever in Chicken Soup for the Teenage Soul Ⅱ.I felt so much better after reading it. It was like a weight had been lifted from me when I realized that many friendships went through changes and that we weren’t the only friends to experience them.
People change, but that doesn’t mean we have to lose the friendships we once shared. My friends and I still spend time together when we can and care about each other a lot. That things are different doesn’t mean I have to forget about all the good times we had. I will always keep the memories in a safe place in my heart.
Sincerely,
Peter
【小题1】According to the author, parents and grandparents
| A．didn’t have to overcome difficulties when in their teens. |
| B．don’t fully understand the pressures of being a teenager now |
| C．can easily deal with things such as choosing friends and shoes. |
| D．don’t need to give help to teenagers with pressures and problems |
| A．Because he was afraid that he had lost his friends. |
| B．Because he and his friends weren’t in the same school. |
| C．Because he was too busy to be with his friends. |
| D．Because his friends refused to hang out with him. |
| A．Friendships． | B．Changes． | C．Friends． | D．Pressures |
| A．people change but friendships always last. |
| B．changes sometimes cause hurt and confusion |
| C．people will go through many changes in life |
| D．friendships should be kept with skills |