您所在的当前位置：高中物理试题 >

匀变速直线运动

> 在光滑足够长的斜面上，有一物体以10 m/s初速度沿斜面向上运动，如果物体的加速度始终为5m/s 2,方向沿斜面向下。那么经过3 s时的速度大小和方向是： ( ) A．25m/s,沿斜面向上 B．5m/s , 沿斜面向下 C．5m/s, 沿斜面向上 D．25m/s,沿斜面向下

问题：

发布时间：2024-09-13

在光滑足够长的斜面上，有一物体以10 m/s初速度沿斜面向上运动，如果物体的加速度始终为5m/s ²,方向沿斜面向下。那么经过3 s时的速度大小和方向是： ( )

A．25m/s,沿斜面向上

B．5m/s , 沿斜面向下

C．5m/s, 沿斜面向上

D．25m/s,沿斜面向下

参考答案：

提问用户：nw***b29

可能感兴趣的题目：

1 南极最低气温达-89.2℃，参考下表资料，要测南极的气温，应选用 A.酒精温度计 B.煤油温度计 C.水银温度计 D.都可以
2 阅读理解。 On Nov.18th,1908,three men went up in a balloon (气球).They started early in London. The headman was Auguste Gaudron,and the other two men were Tannar and Maitland. They had a big balloon and they were ready for a long way. Soon they heard the sea. They were carrying the usual rope (绳子),and it was hanging down from the basket of the balloon. At the end of the rope they had tied a metal box. This could hold water, or it could be empty. So they were able to change its weight (重量). It was for use over the sea. They were also carrying some bags of sand. After the sun rose, the balloon went higher. It went up to 3,000 metes, and the air was very cold. The water in the balloon became ice. Snow fell past the men"s basket, and they could see more snow on the ground. The men tried to throw out some more sand; but it was hard. They tried to break the icy sand with their knives, but it was not easy. The work was slow and they were still falling, so they had to drop some whole bags of sand. One of them fell on an icy lake and made a black hole in the ice. At last they pulled the box into the basket. It was still snowing; so they climbed to get away from the snow. They rose to 5,100 metes! Everything became icy. They were so cold that they decided to land. They came down in Poland heavily but safely. They had traveled 1,797 kilometers from London! 1.Three men flew in balloon ________. A. for nearly 1,800 kilometers B. to another city C. to visit Poland D. more than a century ago 2.The metal box was used for ________. A. carrying the bags of sand" " B. keeping drinking-water C. carrying ropes of the basket D. changing weight 3.When the balloon went up higher,________. A. the temperature of the balloon began to fall B. They saw the sun go down C. They made a hole in the basket with their knives D. They could see a black hole on the ground 4.The balloon landed ________. A. in London B. on the sea C. on a lake D. in a foreign country 5.Which of the following is NOT true ________ A The three men started their journey before the sun rose. B. The balloon began to go up when they threw bags of sand out of the basket. C. When they pulled the box into the basket, the balloon began to climb up. D. The three men had to land because they felt cold.
3 下列指定溶液中，各组离子可能大量共存的是（　　） A．pH=1的溶液中：K+、Fe2+、C1-、NO3- B．加入Al能放出H2的溶液中：NH4+、SO42-、C1-、HCO3- C．在含有大量Fe3+的溶液中：NH4+、C1-、Na+、SCN- D．由水电离的c（OH-）=10-13mol•L-1的溶液中：Ba2+、Na+、C1-、Br-
4 如图程序运行结果是______．
5 若非零向量a，b满足| ，则a与b的夹角为 A．300 B．600 C．1200 D．1500
6 _____ and the problem could be settled. [ ] A. A bit more effort B. To make more effort C. Making more effort D. If you make more effort
7 有一支刻度均匀但读数不准的温度计，用它测量冰水混合物的温度时，读数是4℃；用它测量1标准大气压下沸水的温度时，读数为96℃．用这支温度计去测一杯热水的温度，当它的读数是50℃时，这杯热水的真实温度是 A.46℃ B.48℃ C.50℃ D.54℃
8 完形填空。 I was tired and hungry after a long day of work. When I walked into the living-room, my 12-year-old son looked up at me and said, "I 1 you." I did not 2 what to say, and I just stood there, looking 3 at him. My first 4 was that he 5 need help with his homework. Then I asked, "What was that all 6 ?" "Nothing," he said, "My teacher said we should tell our parents we love them and 7 what they say." The next day I called his teacher to 8 more about what my son said and how the other parents had reacted( 反应 ). "Most of the fathers had the 9 response as you did," the teacher said, "When I first 10 that we try this, I asked the children 11 they thought their parents 12 say. Some of them thought their parents would have heart trouble." Then the teacher 13 , " I want my students to know that feeling love is an important part of 14 . I"m trying to tell them it"s too bad that we don"t express (表达) our feelings. A boy 15 tell his father or mother he loves him." The teacher understands that sometimes it is 16 for some of us to say something that is good for us to say. That evening when my son 17 to me, I took him in my arms and held on for an 18 moment, saying, "Hey, I love you, 19 ." I don"t know if saying that made 20 of us healthier, but it did feel pretty good. ( )1. A. hate ( )2. A. realize ( )3. A .away ( )4 A . thought ( )5. A. must ( )6. A. for ( )7. A. test ( )8. A . talk to ( )9. A. same ( )10. A. allowed ( )11. A. how ( )12. A. would ( )13. A. explained ( )14. A. study ( )15. A. might ( )16. A. easy ( )17. A. turned ( )18. A. extra ( )19. A. either ( )20. A. all B. love B. recognize B. for B. meaning B. should B. with B. know B. chat with B. different B. agreed B. whether B. will B. prepared B. work B. can B. difficult B. shouted B. ordinary B. too B. either C. like C. know C. down C. news C. could C. around C. understand C. find out C. usual C. planned C. when C. could C. informed C. health C. should C. crazy C. went C. interesting C. also C. none D. enjoy D. find D. on D. reason D. would D. about D. see D. do with D. unusual D. suggested D. what D. can D. developed D. body D. need D. silly D. came D. important D. again D. neither
9 某溶液中存在大量的H +、Cl -、SO 4 2-，该溶液中还可能大量存在的是（　　） A．HCO3- B．Ba2+ C．Al3+ D．Ag+
10 从静止开始做匀加速直线运动的物体，前10s内的位移是10m，则该物体运动30s时的位移为( ) A．30m B．60m C．90m D．120m