题干

若声音在海水中的传播速度为1500m/s,利用回声定位原理从海面竖直向海底发射超声波,到接受回声所用时间为4s,那么该处海洋的深度为多少?
上一题 下一题 0.0难度 选择题 更新时间:2019-05-19 09:03:13

答案(点此获取答案解析)

解:超声波从海面到海底用的时间:t=
1
2
×4s=2s,
该处海水的深度:h=vt=1500m/s×2s=3000m.
答:海洋中该处的深度是3000m.

同类题4

阅读短文,完成下列问题。

    In her outstanding book, “Choose the Happiness Habit”, Pam Golden wrote, “Take the story of two twin brothers for example. One grew up and became an alcoholic (酒鬼), while the other became a successful businessman. When asked why he became an alcoholic, the alcoholic replied, “Because my father was a drunk.” However, the successful businessman's answer was also “Because my father was a drunk.” when asked why he succeeded. The same background. The same upbringing (培养). However, the results were quite different. Why? The reason is that they had different choices. The brothers chose different thoughts which formed the situations they found themselves in at last, so they had different experiences.

    There was a time in my life when I thought difficulty was due to “bad luck”. Have you ever heard the saying “When it rains, it pours”? That was my answer when others asked me how things were going on when I was in trouble. So what do you think I got? “RAIN”. More and more “RAIN”. I couldn't understand why bad luck was always with me.

    Pam Golden says, “You're either living in the problem or you're living in the solution.” Now, when I'm faced with what I used to think was a negative (消极的) situation, I use a different way to think about it. I force myself to replace those negative thoughts that make me lose heart in my mind with positive thoughts which encourage me to fight against the difficulty bravely. Sometimes I write down some ideas that may be a solution, which I combine with the lessons I have learned from the bad situations and the difficulties that troubled me in the past, and often, I find a solution to the problem soon. It seems that I should thank the difficulty I met with. The RAIN that poured in my world has become great experiences that provide me with valuable experience, from which I can benefit.

    Now, it doesn't “rain” as much in my life as it used to. In fact, most days are beautiful, cloudless and sunny! Sometimes I do get a rain, but I think it makes me stronger just like the rain helps plants grow up.