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物理 高校生

物理の問題の(2)についてわからないところがあります。 Asin(2πft+π)にはマイナスがなく、どうして、-Asin2πftにはマイナスがあるのですか。

218. 単振動の式 原点Oを中心として,x軸上で単振動をする物体があ る。 この単振動の振幅は A[m〕 振動数はf [Hz] である。 物体が, 原点O を負の向きに通過する時刻を t=0 とする。この単振動について,次の各 問に答えよ。 Ons st (1) 角振動数を求めよ。 (2) 時刻 (0) における変位 x [m] を表す式を示せ。 (3) 速さの最大値を求めよ。 (4) 加速度の大きさの最大値を求めよ。 例題 30 ヒント (2) 物体は, t=0 において原点を負の向きに通過するため、 初期位相は"となる。 PRAUDONES (1) 218. 単振動の式 解答 (1) 2f [rad/s] (2) x=Asin (2ft+m) [m] (x=-Asin2πft [m]) (3) 2πfA [m/s] (4) 47²f2A (m/s²) 指針 単振動における変位の式は,初期位相が0のとき, 角振動数を w とすると, x=Asin (wt+0) と表される。 また, 振幅をAとすると, 速さの最大値は v = Aω, 加速度の最大値は α = A ω² となる。 2π W= -=2πf [rad/s〕 T 2π 解説 (1) 角振動数ω [rad/s] は、 周期T 〔s] を用いて, w= と表 T される。 T= の関係を用いると, f (2) 原点を負の向きに通過する時刻を t=0 とし ており, 初期位相はπである (図)。 求めるxの 式は, (1) のω=2πf の関係を用いて, x=Asin(wt+0)=Asin (2πft+™) [m] (またはx=-Asin2πft〔m〕) (3) 速さの最大値は, v=Aw [m/s] なので, w=2πfの関係を用いて, v=Aw=2πfA[m/s] x[m] A π -A• 初期位相π(t=0) Ax 0 (4) 加速度の大きさの最大値は, a = Aw2 から, w=2πf の関係を用い t=0 自 には は正を本過り 正の を言 本間

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英語 中学生

解説してもらえませんか?

あと 次は,中学生のタケシ ( Takeshi) が書いたスピーチの原稿 の1~6の問いに答えなさい。 I am going to talk about my interesting experience. I went to London during this summer vacation with my family. This was my first trip to a foreign country. I wanted to know about London, so I looked for information about it on the Internet. I was able to see many famous things on the Internet before the trip. In London, we went to some popular places, for example, Buckingham Palace and Tower Bridge. I already saw them on the Internet, but they looked bigger and more beautiful to me when I saw them directly. I was ( )! When I walked around, I saw a lot of people from different countries, too. Then, we went to a restaurant to eat local dishes. They were very new to me, but I enjoyed them. When we finished our dinner and left the restaurant at about nine in the evening, I found 2one strange thing. It was not dark outside! I was very surprised. In Fukuoka, it is dark at nine in July, but it is not in London! This was the most interesting thing to me. I enjoyed this trip very much because I was able to discover new things. After the summer vacation, I told my classmates about my trip to London in an English class. Many of them liked my story and I was glad. After school, one of my classmates came to me and said, "I really enjoyed your story. I love Harry Potter, and I'm very interested in London. Can you tell me more about your trip ?" In fact, 3 was surprised when she came to talk to me. Before that, we didn't talk, and I though she was not interested in foreign countries. But that was not right. She knew a lo about London. We talked about my trip and Harry Potter. When we were talking she said to me, "Going abroad is a good way to study, but I have ( ) to Foreign country. I was glad to talk with you." I discovered new things about her o hat day. ) ( 4 You can get information about many things on TV and the Internet, and you ofte hink you know about people around you before talking to them. But you can discove ew things when you experience something directly. I want to remember this idea ar xperience a lot of things in the future. 主) foreign: 外国の Buckingham Palace: バッキンガム宮殿 Tower Bridge: タワーブリッジ directly : 直接に local dishes : その土地の料理 outside: 外で discover : 発見する Harry Potter: ハリー・ポッター

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理科 中学生

(2)の②、③が分かりません。 教えてください🙇

から符号で選びなさい。 AはBより暖かく, CはDより暖かいイAはBより暖かく, DはCより暖かい ウ. BはAより暖かく, CはDより暖かい I 電源装置 A (2) 抵抗の大きさが8Ωの電熱 線Aと抵抗の大きさのわから ない電熱線B,Cがある。 こ の3つの電熱線A~Cのうち 2つを選ぶ3通りの組み合わ せについて,それぞれ図Iのような直 列回路と,図ⅡI のような並列回路をつ くり、電流計を流れる電流の大きさを 電熱線の組み合わせ 直列回路 並列回路 測定した。 表は, 測定段階の途中のものである。 図のX,Yは電流計, 電圧計のいずれかであ り、電源の電圧の大きさはいずれも24Vであるとして,次の ①~④に答えなさい。 ① 図Iで,端子Pは何ですか。 最も適当なものを、次から符号で選びなさい。 ア 電流計の+端子 イ電流計の-端子 A 2819 -9.6 電圧計の+端子 14.4 ② 電熱線Bの抵抗の大きさは何Ω ですか。 ③ 表のQにあてはまる値は何Aですか。 金属などのように, 電気抵抗が小さく電流が流れやすい物質を何といいますか。 電熱線 AU 0000 T X DはCより暖かい エBはAより暖かく, 電熱線 JAWATAN STOPNÉ P 0000 電流計の値 [A] II Y 電源装置 200 9.0A 電圧計の一端子 A Q 電熱線 AとB 8 9.0 電熱線 2.6. AとC 1.2 aban 0000 Y X BとC = 11 FIREAR 3W10421J TR Dolm Bin Stola 1 1 41603/2 3W

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英語 高校生

並べ替えの問題がわかりません🥲教えてくださいお願いします🙇‍♀️

rmativ nt Each of us carries just over 20,000 genes that encode everything from the keratin in our hair down to the muscle fibers in our toes. It's no great (1) (own / came / where / from / our / mystery / genes): our parents bequeathed them to us. And our parents, in turn, got their s genes from their parents. But where along that genealogical line did each of those 20,000 protein-coding genes get its start? That question has hung over the science of genetics (2) (ago / dawn / century / since / a / ever / its). "It's a basic question of life: how evolution generates 1 novelty," said Diethard Tautz of the Max Planck Institute for 10 Evolutionary Biology in Plön, Germany. New studies are now bringing the answer into focus. Some of our genes are immensely old, perhaps (3) (to / way / back / dating / all the / the) earliest chapters of life on earth. But a surprising number of genes emerged more recently. many in just the past few million years. The youngest evolved after our 15 own species broke off from our cousins, the apes. Scientists (4) (being / finding / into / are / genes / come / new) at an unexpectedly fast clip. And once they evolve, they can quickly take on essential functions. Investigating how new genes (5) (understand / help / become / scientists / important / may / so) the role they may play in diseases like cancer. [1] Read the passage and rearrange the seven words in (1) - (5) in the correct order. Then choose from 1-4 the option that contains the third and fifth words. (1) 13rd: our (2) (3) (4) (5) 5th: genes 3rd: ago 5th: since 3rd: back 5th: the 2 3rd: where 5th: came 2 3rd: its 5th: ever 23rd: the 5th: back 2 3rd: genes 5th: into 1 3rd: genes 5th: being 1 3rd: may 5th: scientists 3 3rd: scientists 5th: understand 3 3rd: genes 5th: from 3 3rd: its 5th: a 3 3rd: way 5th: back 3 3rd: finding 5th: genes 23rd: important 5th: help 43rd: help 3rd: own 5th: came 3rd: came 5th: dawn 43rd: the 5th: the 4 3rd: new 5th: come 5th: understand may may understand thep (早稲田大) wystery. ne TOL Recome Sc

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