问题 不定项选择

如图所示,竖直轻弹簧下端固定在水平地面上,质量为m的小球,从轻弹簧的正上方某一高处自由落下,并将弹簧压缩,直到小球的速度变为零.对于小球、轻弹簧和地球组成的系统,在小球开始与弹簧接触时起到小球速度变为零的过程中,有

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A.小球的动能和重力势能的总和越来越小,小球的动能和弹性势能的总和越来越大

B.小球的动能和重力势能的总和越来越小,小球的动能和弹性势能的总和越来越小

C.小球的动能和重力势能的总和越来越大,小球的动能和弹性势能的总和越来越大

D.小球的动能和重力势能的总和越来越大,小球的动能和弹性势能的总和越来越小

答案

答案:A

填空题

We already live in an ever-communicated world that will only become mere so in the next tech era. We’ve (1) that gets us so much information. We’ve got every second (2) , we’ve get computers and laptops, we’ve get personal organizers and we’re just being (3) and every advance in technology seems to create more and more communications at us. We are sort of (4) .
Research suggests that all the multi-tasking may actually make our brains (5) , producing a world-wide increase in IQ (6) and mere in recent decades. Is there any real benefit in (7) we new have to go through
We’re net becoming a race of (8) , but many de think certain skills are enhanced and certain are net. You knew the ability to (9) , to answer a dozen e- mails in five minutes, or to fill out (10) . That’s enhanced. But when someone is out there with his kids (11) or something like that, he’s got his cell phone in his pocket. He’s always wondering, "Gee, did I get a voicemail " This might have negative effects (12) .
Creativity is something that happens slowly. It happens when your brain is just (13) , just playing, when it (14) which you hadn’t thought of, or maybe you have time to read a book. You are a businessperson but you have time to (15) ,or about a philosopher and something that happened long age or something or some idea (16) . Actually, it might occur to you that you (17) in that way, and so it’s this mixture of unrelated ideas that feeds your productivity, (18) . And if your mind is disciplined to answer every e-mail, then you don’t have time for that playful noodling. You don’t have time for (19) . So I think maybe we’re getting smarter in .some senses, but ever-communication is (20) and to our reflection.

We already live in an ever-communicated world that will only become mere so in the next tech era. We’ve (1) that gets us so much information. We’ve got every second (2) , we’ve get computers and laptops, we’ve get personal organizers and we’re just being (3) and every advance in technology seems to create more and more communications at us. We are sort of (4) .
Research suggests that all the multi-tasking may actually make our brains (5) , producing a world-wide increase in IQ (6) and mere in recent decades. Is there any real benefit in (7) we new have to go through
We’re net becoming a race of (8) , but many de think certain skills are enhanced and certain are net. You knew the ability to (9) , to answer a dozen e- mails in five minutes, or to fill out (10) . That’s enhanced. But when someone is out there with his kids (11) or something like that, he’s got his cell phone in his pocket. He’s always wondering, "Gee, did I get a voicemail " This might have negative effects (12) .
Creativity is something that happens slowly. It happens when your brain is just (13) , just playing, when it (14) which you hadn’t thought of, or maybe you have time to read a book. You are a businessperson but you have time to (15) ,or about a philosopher and something that happened long age or something or some idea (16) . Actually, it might occur to you that you (17) in that way, and so it’s this mixture of unrelated ideas that feeds your productivity, (18) . And if your mind is disciplined to answer every e-mail, then you don’t have time for that playful noodling. You don’t have time for (19) . So I think maybe we’re getting smarter in .some senses, but ever-communication is (20) and to our reflection.

单项选择题