您所在的当前位置：高中物理试题 >

电荷在电场中的偏转

> ．如图所示，地面上某区域存在着竖直向下的匀强电场，一个质量为m的带负电的小球以水平方向的初速度v0由O点射入该区域，刚好通过竖直平面中的P点，已知连线OP与初速度方向的夹角为45°，则此带电小球通过P点时的动能为 (　　) A．mv B．mv C．2mv D．mv

问题：

发布时间：2024-09-09

．如图所示，地面上某区域存在着竖直向下的匀强电场，一个质量为m的带负电的小球以水平方向的初速度v0由O点射入该区域，刚好通过竖直平面中的P点，已知连线OP与初速度方向的夹角为45°，则此带电小球通过P点时的动能为 (　　)

A．mv B．mv

C．2mv D．mv

参考答案：

提问用户：A8***6Bk

可能感兴趣的题目：

1 ______ the danger from wars, people had to deal with a shortage of food, clothing, fuel and almost everything. A．In spite of B．Instead of C．As long as D．As well as
2 下列判断正确的是 A.皮球落地的瞬间，力的作用效果是改变了皮球的形状 B.熟透了的苹果落向地面的过程中，因为方向没有变化，它的运动状态不发生变化 C.相互作用的一对力一定作用在同一个物体上 D.匀速直线上升的气球的运动状态可能改变
3 C Holding a cell phone against your ear or storing it in your pocket may be dangerous to your health. This explains a warning that cell phone manufacturers include in the small print that is often ignored when a new phone is purchased. Apple, for example, doesn’t want iPhones to come closer to you than 1.5 centimeters; Research In Motion, BlackBerry’s manufacturer, recommends 2.5 centimeters. If health issues arise from cell phone use, the possible effects are huge. Voice calls - Americans chat on cell phones 2.26 trillion(万亿)minutes annually - earn $109 billion for the wireless carriers. Devra Davis, an expert who has worked for the University of Pittsburgh, has published a book about cell phone radiation, “Disconnect.” The book surveys scientific research and concludes the question is not settled. Brain cancer is a concern that Ms. Davis examines. Over all, there has not been an increase in its incidence since cell phones arrived. But the average masks an increase in brain cancer in the 20-to-29 age group and a drop for the older population. “Most cancers have multiple causes,” she says, but she points to laboratory research that suggests low-energy radiation could damage cells that could possibly lead to cancer. Children are more vulnerable to radiation than adults, Ms. Davis and other scientists point out. Radiation that penetrates only five centimeters into the brain of an adult will reach much deeper into the brains of children because their skulls are thinner and their brains contain more absorptive fluid（易吸收的液体）. No studies have yet been completed on cell phone radiation and children, she says. Henry Lai, a research professor in the bioengineering department at the University of Washington, began laboratory radiation studies in 1980 and found that rats exposed to radiation had damaged DNA in their brains. Ms. Davis recommends using wired headsets or the phone’s speaker. Children should text rather than call, she said, and pregnant women should keep phones away from the abdomen（腹部）. 小题1:Why is the warning in the small print? A．They think people will not care about it. B．There is not enough space for the warning. C．They don’t want the users to pay attention to it. D．The warning is not important at all. 小题2: What does the underlined word in sixth paragraph probably mean? A．acceptable B．valuable C．accessible D．easily affected 小题3:What can we conclude from the last paragraph? A．Pregnant women should keep cell phones away. B．People should use cell phones in the correct way. C．If you are a child, you’d better text than make phone calls. D．When you use a cell phone, use a wired headset or the phone’s speaker. 小题4: What does the passage mainly talk about? A．Be careful when using cell phones. B．Don’t hold your cell phone against your ear. C．Rats exposed to radiation have damaged DNA in their brains. D．Low-energy radiation could damage cells that could lead to cancer.
4 20世纪80年代以来，某钢铁企业若考虑经济效益，在布局上选择该图中哪一点最适宜 A．甲地 B．乙地 C．丙地 D．丁地
5 漫画《逆风的方向，更适合飞翔》给我们的启示是(　　) A．矛盾双方在一定条件下可以相互转化 B．要善于抓住复杂事物的主要矛盾 C．积极做好量的积累为质变创造条件 D．在绝对运动与相对静止中把握物质的根本属性
6 下面是一个物理演示实验，它显示：如图5-2-9中自由下落的物体A和B经反弹后，B能上升到比初始位置高得多的地方.A是某种材料做成的实心球，质量m 1="0.28" kg，在其顶部的凹坑中插着质量m 2="0.10" kg的木棍B.B只是松松地插在凹坑中，其下端与坑底之间有小空隙.将此装置从A下端离地板的高度H="1.25" m处由静止释放.实验中，A触地后在极短时间内反弹，且其速度大小不变；接着木棍B脱离球A开始上升，而球A恰好停留在地板上.求木棍B上升的高度.重力加速度g取10 m/s 2. 图5-2-9
7 用400N的力在水平地面上拉车行走50m，拉力与车前进的方向成30°角。那么，拉力对车做的功是( ) A．2.0×104J B．1.0×104J C．1.7×104J D．以上均不对
8 SiCl 4的分子结构与CCl 4类似，对其作出如下推测，则其中不正确的是 [ ] A．SiCl 4晶体是分子晶体 B．SiCl 4的熔点高于CCl 4的 C．SiCl 4的分子是由极性键形成的非极性分子 D．常温常压下，SiCl 4是气体
9 What ___ of blood does Jack have? A．sort B．type C．category D．kind
10 汽车做匀加速直线运动，路旁每两根电线杆之间的间隔都是50m，汽车通过第一个间隔的时间是5s，通过第二个间隔的时间是4s。求汽车运动的加速度。