您所在的当前位置：高中物理试题 >

匀变速直线运动

> 一个物体作直线运动，计算机扫描仪输出的该物体的位移随时间变化的函数关系是S=2t 2+4t (m), 则根据此函数式可以得到它运动的初速度和加速度分别是（） A．0、4m/s2 B．4m/s、2m/s2 C．4m/s、1m/s2 D．4m/s、4m/s2

问题：

发布时间：2024-09-08

一个物体作直线运动，计算机扫描仪输出的该物体的位移随时间变化的函数关系是S=2t ²+4t (m), 则根据此函数式可以得到它运动的初速度和加速度分别是（）

A．0、4m/s² B．4m/s、2m/s² C．4m/s、1m/s² D．4m/s、4m/s²

参考答案：

提问用户：Nq***BLu

可能感兴趣的题目：

1 根据影响农业生产和布局的主要因素，上海市近郊农业发展的重点是 A．大量种植棉花，为纺织工业提供原料 B．发展蔬菜、肉、蛋、奶以及园艺业 C．利用优越的水热条件种植水稻，使上海实现粮食自给 D．营造用材林，为工业部门和建筑业提供木材
2 如图所示，长为L的木板A静止在光滑的水平桌面上，A的左端上方放有小物体B（可视为质点），一端连在B上的细绳，绕过固定在桌子边沿的定滑轮后，另一端连在小物体C上，设法用外力使A、B静止，此时C被悬挂着。A的右端距离滑轮足够远，C距离地面足够高。已知A的质量为6m，B的质量为3m，C的质量为m。现将C物体竖直向上提高距离2L，同时撤去固定A、B的外力。再将C无初速释放，当细绳被拉直时B、C速度的大小立即变成相等，由于细绳被拉直的时间极短，此过程中重力和摩擦力的作用可以忽略不计，细绳不可伸长，且能承受足够大的拉力。最后发现B在A上相对A滑行的最大距离为。细绳始终在滑轮上，不计滑轮与细绳之间的摩擦，计算中可认为A、B之间的最大静摩擦力等于滑动摩擦力，取重力加速度g=10m/s 2。（1）求细绳被拉直前瞬间C物体速度的大小υ 0；（2）求细绳被拉直后瞬间B、C速度的大小υ；（3）在题目所述情景中，只改变C物体的质量，可以使B从A上滑下来。设C的质量为km，求k至少为多大？
3 The beggar has no money with which to buy food. However, no passers-by ______ him. A．have mercy on B．are at the mercy of C．show mercy on D．to be merciful to
4 将漫射日光照射到装有氯气和甲烷混合气体（体积比4：1)的装置上将发生：①试管内黄绿色逐渐消失②试管内黄绿色加深③无任何现象④试管内液面上升⑤液面上的试管内壁有油状物生成，其中正确的是 A．只有③ B．①④⑤ C．①⑤ D．②⑤
5 两个轻小物体相互吸引时 A.两物体必定带有异种电荷 B.两物体必定带有同种电荷 C.其中一物体肯定带电荷，而另一物体不一定带电荷 D.以上都对
6 阅读理解。 We have two daughters: Kristen is seven years old and Kelly is four. Last Sunday evening, we invited some people home for dinner. I dressed them nicely for the party, and told them that their job was to join Mommy in answering the door when the bell rang. Mommy would introduce them to the guests, and then they would take the guests"coats upstairs and put them on the bed in the second bedroom. The guests arrived. I introduced my two daughters to each of them. The adults were nice and kind and said how lucky we were to have such good kids. Each of the guests made a particular fuss over Kelly, the younger one, admiring her dress, her hair and her smile. They said she was a remarkable girl to be carrying coats upstairs at her age. I thought to myself that we adults usually make a big "to do" over the younger one because she"s the one who seems more easily hurt. We do it with the best of intentions. But we seldom think of how it might affect the other child. I was a little worried that Kristen would feel she was being outshined. I was about to serve dinner when I realized that she had been missing for twenty minutes. I ran upstairs and found her in the bedroom, crying. I said, "What are you doing, my dear?" She turned to me with a sad expression and said,"Mommy, why don"t people like me the way they like my sister? Is it because I"m not pretty? Is that why they don"t say nice things about me as much?" I tried to explain to her, kissing and hugging her to make her feel better. Now, whenever I visit a friend"s home, I make it a point to speak to the elder child first. 1. What did the parents ask the sisters to do to welcome the guests? A. To introduce themselves to the guests B. To put away the guests" coats in another upstairs room. C. To take off the guests" coats politely. D. To entertain the guests with candies. 2. The underlined expression" make a big "to do" over" (paragraph 4) means ______. A. show much concern about B. have a special effect on C. list jobs to be done for D. do good things for 3. The guests praised Kelly for carrying coats upstairs because of her ______. A. beautiful hair B. pretty clothes C. lovely smile D. young age 4. Kristen felt sad and cried because ______. A. the guest gave her more coats to carry B. she didn"t look as pretty as Kelly C. the guests praised her sister more than her D. her mother didn"t introduce her to the guests 5. We can conclude from the passage that ______. A. parents should pay more attention to the elder children B. the younger children are usually more easily hurt C. people usually like the younger children more D. adults should treat children equally
7 2010年10月1日，嫦娥二号卫星发射成功．作为我国探月工程二期的技术先导星，嫦娥二号的主要任务是为嫦娥三号实现月面软着陆开展部分关键技术试验，并继续进行月球科学探测和研究．如图，嫦娥二号卫星的工作轨道是100公里环月圆轨道Ⅰ，为对嫦娥三号的预选着陆区——月球虹湾地区（图中B点正下方）进行精细成像，嫦娥二号在A点将轨道变为椭圆轨道Ⅱ，使其近月点在虹湾地区正上方B点，大约距月面15公里．下列说法中正确的是 A．沿轨道Ⅱ运动的周期大于沿轨道?运动的周期 B．在轨道Ⅱ上A点的速度大于在轨道?上A点的速度 C．完成任务后，卫星返回工作轨道Ⅰ时，在A点需加速 D．在轨道Ⅱ上A点的加速度大于在轨道?上A点的加速度
8 某无色溶液中，由水电离出的c(H +)＝1×10 -14 mol/L，则该溶液中，一定能大量共存的离子是 [ ] A． K +、Na +、MnO 4 -、SO 4 2- B．Na +、CO 3 2-、[Al(OH) 4] -、Cl - C．K +、Na +、Cl -、Br - D．K +、Cl -、Ba 2+、HCO 3 -
9 It was about 600 years ago _______ the first clock with a face and an hour hand was made. A．that B．until C．before D．when
10 不同地区的气候条件适宜不同的水果生长，据此判断：下列某超市水果区货架上的标签中，产地标注错误的是 A.香蕉产地：中国台湾 B.椰子产地：中国海南 C.柑橘产地：中国黑龙江 D.苹果产地：中国山东

一个物体作直线运动，计算机扫描仪输出的该物体的位移随时间变化的函数关系是S=2t 2+4t (m), 则根据此函数式可以得到它运动的初速度和加速度分别是（ ） A．0、4m/s2 B．4m/s、2m/s2 C．4m/s、1m/s2 D．4m/s、4m/s2

可能感兴趣的题目：

一个物体作直线运动，计算机扫描仪输出的该物体的位移随时间变化的函数关系是S=2t ²+4t (m), 则根据此函数式可以得到它运动的初速度和加速度分别是（）

A．0、4m/s² B．4m/s、2m/s² C．4m/s、1m/s² D．4m/s、4m/s²