您所在的当前位置：高中物理试题 >

力的合成

> 船的静水航速保持5m/s不变，水流的速度恒定为3m/s，则河岸上的人看到船的实际速度大小可能是（　　） A．3m/s B．5m/s C．7m/s D．9m/s

问题：

发布时间：2024-09-07

船的静水航速保持5m/s不变，水流的速度恒定为3m/s，则河岸上的人看到船的实际速度大小可能是（　　）

A．3m/s B．5m/s C．7m/s D．9m/s

参考答案：

提问用户：uw***Dct

可能感兴趣的题目：

1 One advantage of G3 mobiles is that it has become a very useful tool for________daily communication. [ ] A. taking on B. speeding up C. working on D. making up
2 It’s really the Greens devote all their money to helping the poor . A．generous for B．generous of C．generous that D．generous to
3 December 2 Sharon called about four times today. At least it shows she"s trying to explain something to me. I feel a little better. December 3 This morning Sharon said she had only told one person and didn"t know why everyone seemed to know. Yes, I am an adopted (收养的) daughter. But she had promised to keep it a secret for ever! December 5 I wish I had a friend I could really trust all of the time. I thought I found that friend, but I haven"t and it"s making me miserable (痛苦的)! It"s wrong to tell her all about it. She gains my trust, and then loses it. December 7 I have a nice room, beautiful house and everything I"ve ever wanted. My adoptive parents will give me all the things I"ve ever dreamed of. Yet all the money in the world can"t buy what I want now. I want for Sharon to be my best friend again. December 10 Sharon just called. She said she thought it might help if we spent more time together. She worried that I would switch schools (转学). She is the best friend I"ve ever had. When I"m with Sharon, I can be myself. I need Sharon"s friendship. I need it more than I"ve ever known. December 16 I just had the most fantastic two days of my life! This was the best time I"ve had for a long, long while. Yesterday, we walked five times around the park and today we walked along the river for twenty minutes. We talked so much. Sharon, Sharon, no brick wall between us now. 1. What is the author mainly worried about? A. How she was adopted. B. Why she switched schools. C. Her family life. D. Her friendship with Sharon. 2. Sharon lost the author"s trust because she ________. A. didn"t keep the author"s sec ret B. didn"t like the author any more C. told the author"s past life to everyone D. often refused to h elp the author 3. The underlined word "fantastic" in the last paragraph probably means ________. A. funny B. wonderful C. sad D. lucky 4. It can be inferred that in the end the author and Sharon ________. A. were not friends anymore B. became good friends a gain C. would switch to another school together D. could hardly understand each other
4 一波源在绳子的左端发生波P，另一波源在同一根绳子右端发生波Q，波速为lm／s。在t＝0时绳上的波形如图中a所示，根据波的叠加原理，以下判断正确的是 [ ] A．当t＝2s时，波形图如b图，t＝4s时，波形图如c图 B．当t＝2s时，波形图如b图，t＝4s时，波形图如d图 C．当t＝2s时，波形图如c图，t＝4s时，波形图如b图 D．当t＝2s时，波形图如c图，t＝4s时，波形图如d图
5 打开收音机的开关．将旋钮凋到没有电台的位置，并将音量开大，如图所示，从一节干电池的负极引出一根电线与一个铁锉相连，正极引一根导线在铁锉上来回刮动，收音机会发出______，这个现象说明：______．
6 有几位同学议论电磁波时，有以下几种说法，你认为不正确的是（） A．电磁波是由方向来回变化的电流产生的 B．通常使用的无线电波的频率为数百千赫至数百兆赫的那一部分 C．电磁波的频率等于一秒内电流振荡的次数 D．电磁波的波长就是电流每振荡一次电磁波向前传播的距离
7 已知a，b都是实数，那么“a＞b”是“a 2＞b 2”的（　　） A．充分而不必要条件 B．必要而不充分条件 C．充分必要条件 D．既不充分也不必要条件
8 指出下面句子中“在”的词性。 A．他在教室（　） B．他在操场打球（　）
9 古诗文填空。（5题限选4题）（8分）（1）子曰：“饭疏食饮水，，乐亦在其中矣！，于我如浮云。”（《论语·述而》）（2）不有佳咏，？如诗不成，。（李白《春夜宴从弟桃花园记》）（3），依依墟里烟。狗吠深巷中，。（陶渊明《归园田居（其一）》）（4），微冷，山头斜照却相迎。，归去，也无风雨也无晴。（苏轼《定风波》）（5）有志与力，，，亦不能至也。（王安石《游褒禅山记》）
10 如图所示，两列简谐横波分别沿x轴正方向和负方向传播，两波源分别位于x=－2×10 -1m和x=12×10 -1m处，两列波的波速均为v=0.4m/s，两波源的振幅均为A=2cm。图示为t=0时刻两列波的图象（传播方向如图），此刻平衡位置处于x=0.2m和0.8m的P、Q两质点刚开始振动。质点M的平衡位置处于x=0.5m处，关于各质点运动情况判断正确的是 [ ] A．质点P、Q都首先沿y轴正向运动 B．t=0.75s时刻，质点P、Q都运动到M点 C．t=1s时刻，质点M的位移为+4cm D．t=1s时刻，质点M的位移为－4cm

船的静水航速保持5m/s不变，水流的速度恒定为3m/s，则河岸上的人看到船的实际速度大小可能是（ ） A．3m/s B．5m/s C．7m/s D．9m/s

可能感兴趣的题目：

船的静水航速保持5m/s不变，水流的速度恒定为3m/s，则河岸上的人看到船的实际速度大小可能是（　　）

A．3m/s B．5m/s C．7m/s D．9m/s