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Physics Senior High

有効数字をかんがえると答えは0.4になると思うのですがなぜ0.40になるのでしょうか❓

COLOR 2 の加速度は の合力によって生じているので, 運動方程式は ma=mg-T よってT=m(g-a) = 2.0×(9.8-5.6)=8.4N (2) Aの加速度は張力Tによって生じているので,Aにつ いて運動方程式を立てると. Ma=T よって M= T 8.4 a 5.6 -= 1.5kg 47. Point! 物体が動きだす直前にも力のつりあ いは成りたっている。 静止摩擦力は,物体が動 きだす直前には最大摩擦力 「μN」になってい る。 解 (1) 物体にはたらく力は 図 a のようになる。 水平方向に ついての力のつりあいより 5.0-f=0 ① 式より N = 2.5×9.8 これを②式に代入して 9.8-μ×2.5×9.8=0 よって μ= -=0.40 1 2.5 2.5kg 垂直抗力 N 補足 ら、最大摩擦力の式 「μN 」 は使えない。 ① よって f=5.0N (2) 物体が受ける垂直抗力の大き さをNとする。 F 9.8N に なった瞬間、静止摩擦力は最大 摩擦力μNになっており, 物体 にはたらく力は図bのようにな ▼ 2.5×9.8N 図 b る。 動きだす直前は力のつりあいが成りたっているので, ① 鉛直方向, 水平方向についての力のつりあいより 鉛直方向 N-2.5×9.8=0 Mos 水平方向 9.8-μN = 0 重力 N F=5.0N ① 図 a F=9.8N 5.0Nのときは動きだす直前ではないか 注力Fが すべりだす瞬間は最大 Fo=2μN ①~③式より T=Fo=2μmg (2)物体にはたらく力は図bのよ なる。 鉛直方向について力のつりあい N-mg=0 よって N=mg 動摩擦力「μ'N」はμmg と 水平方向について,運動方程 ma=4μmg-μmg a=3μg 〔m/s²] よって

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English Senior High

これの100字要約日本語でしていただけませんか?

5 19 A concerted drive to reduce obesity in one Australian town resulted in a whole generation of slimmer, faster, and healthier children, researchers reported yesterday. They said that the program, a simple mixture of persuasion and (A)incentives, was astonishingly successful. It led to 2,000 children gaining less weight, watching far less television, taze (and playing more sports. The "Be Active, Eat Well" project, conducted by Deakin University in the small town of Colac, 150 km southwest of Melbourne, ended with Colac's children weighing an average of one kilogram less than the norm for Australian children of their age. Their waistlines were an ウェスト average of cm smaller - 2 cm for boys and 4 cm for girls. Professor Boyd Swinburn from Deakin University in Melbourne said yesterday that the Colac experiment had proved to be "astonishingly successful." It was the first such program in the world to report significant reductions in waistline and weight. Professor Swinburn said: "Most people would think individual weight loss of one kilogram is not much, but here we're talking about shifting the weight of a couple of thousand kids, and 15 that's actually quite (B) phenomenal. In fact, across a population, that is absolutely huge." The experiment began three years ago when the university researchers descended on Colac's population of about 10,000 people, urging parents, teachers, doctors, and local fast-food outlets to support changes for all children aged between 4 and 12. The program included opening up more after-school activity centers for children and introducing 20 brightly colored lunch packs that contained a pitta salad wrap*¹ and fruit tub2. Parents were encouraged to (c) monitor strictly the amount of time their children watched television or walk or cycle to They were asked to encourage their children spent on computers. (3) school rather than drive them. While the researchers had hoped to cut television viewing by 10 percent, the final results 25 reported children's television viewing had dropped by 21 percent and soft drink consumption by 70 percent. There was an increase of almost 70 percent in the number of children participating in after-school sports. 10 7. ★★★ 参照チェックノート p.38 414 words 56 早稲田大学 Even the town's fish and chip shop owner switched from using animal fats to sunflower oil. He reduced the saturated fats3 in chips from 49 percent to 9.1 percent. The other fast-food outlets 30 also switched from animal fats, leading to a cut in saturated fats consumed in the town of 55 kg a week. Adults then began to follow their children's example, and the local self-defense academy went from 16 members to 75. pitta satu 1 (A (

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