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理科 中学生

中学校音の単元です。 誰か教えてください。 答えは バスドラム: ア、イ フルート:ア、ウ、エ ピアノ:エ です。 解説よろしくお願いします… お願いします…

WY [7 次の[会話文]は音について,ゆうかさん、たけしさん、さとるさんの3人でかわされた内容 である。 次の問いに答えなさい。 [会話文 ] ゆうか:この前オーケストラの演奏を鑑賞したけど、色々な楽器がそれぞれ違う高さや大きさ の音を出して,それが1つの曲になってすばらしかったです。 たけし:人間の耳に聞こえる音はだいたい20Hzから20000Hz の間の音らしいですね。 さとる :バスドラム *は25Hz~80Hz, フルートは250Hz~2000Hz, ピアノは30Hz~4000Hz の音が出せるらしいです。 ゆうか : 楽器によって全然違うのですね。 さとる : そういえば, ピアノの鍵盤でいうと,真ん中より少し右にあるハ長調のラの音が 440Hz だそうです。 多くの楽器ではこの440Hzでチューニング*2するらしいです。 たけし:それでは,⑥ バスドラム, フルート, ピアノのそれぞれの楽器について,音の高さを いろいろ変えながらオシロスコープの画面で観察してみましょう。 *1 バスドラム : オーケストラで使用する大だいこ *2 チューニング : 楽器の音の高さを合わせること (1) 下線部について, ピアノでこのハ長調のラの音だけをひいたとき, ピアノの弦は5秒間で何回 CHATE

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英語 高校生

(21)の答えが3になるのがなんでか少し分からないです…わかる方いますか??

(21) (22) (23) Any Change? Long ago, humans did not use money. Because they often could not produce everything that they needed, they traded some of their goods for goods made by others. Gradually, the goods that they exchanged were replaced by cash. For hundreds of years, metal coins and paper bills that can be exchanged for goods and services have been produced. Cash is convenient for many people because it is easy to carry. At the same time, though, it ( 21 ). Another disadvantage is that criminals have been able to produce fake coins and bills. In the middle of the 20th century, plastic credit cards were introduced. They had security features to prevent them from being used by anyone except their owners. At first, their use was limited to wealthy people. Over time, however, they became ( 22 ). In the last few years, apps for smartphones that can be used in the same way as credit cards have also become popular. Because of this, some people are suggesting that we may soon see the end of cash. Supporters of a "cashless" society in which all payments are made electronically argue that it would have several benefits. For example, people would not have to worry about keeping their wallets safe. However, some people are concerned that they might be unable to pay for the things they need because of a software error or a broken smartphone. Moreover, some people do not have bank accounts or credit cards, so their only option is to use coins and bills. ( 23 ), it seems as though societies will continue to use cash. 1 can be lost or stolen can be recycled 1 thinner and lighter 3 harder to use 1 For now 2 Until then 2 4 2 4 3 is used for shopping online is understood by almost everyone more colorful and exciting more widely available With luck 4 By contrast

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