Blogtrottr Yahoo!奇摩知識+ - 分類問答 - 科學常識 - 已解決 Yahoo!奇摩知識+ - 分類問答 - 科學常識 - 已解決 Thousands of Free eBooksBookBub brings you free & bargain national bestselling eBooks in the genres of your choice! Sign up now & join 1.5 million happy readers. From our sponsors 物理斜向拋射問題 Oct 1st 2013, 14:33 一石子自斜角A=45°的斜面底端相對於斜面以Q角發射,石子落於斜面的瞬間,速 度方向與斜面垂直,求cotQ=? (1) 求速度 B=A+Q, g=9.8(mps^2), t=time Vx=V*cosB Vy=V*sinB-gt 落下時水平角=-45° => Vx+Vy=0 V*cosB+V*sinB-gt=0 => gt=V(cosB+sinB) (2) 求座標點: 45°斜坡 => x=y x=V*cosQ*t y=V*sinB*t-0.5g*t^2=V*cosQ*t => gt=2V(sinB-cosB) (3) 求cotQ=? 兩者相等: 2(sinB-cosB)=sinB+cosB => sinB=3cosB 3=tanB =tan(Q+45) =(tanQ+tan45)/(1-tanQ*tan45) =(1+tanQ)/(1-tanQ) 1+tanQ=3(1-tanQ)=3-3tanQ 4tanQ=2 => tanQ=1/2 So cotQ=2 This entry passed through the Full-Text RSS service — if this is your content and you're reading it on someone else's site, please read the FAQ at fivefilters.org/content-only/faq.php#publishers. Five Filters recommends: Massacres That Matter - Part 1 - 'Responsibility To Protec...
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