At the scintillating game against the New England Patriots y

qpalzmgh2022-10-04 11:39:542条回答

At the scintillating game against the New England Patriots yesterday,Jeremy Kerley (188 lbs mass) caught a touchdown pass.To catch the ball thrown by Geno Smith he leaped above the defender at the front left corner of the end zone.In the process he first lowered his body to prepare to launch himself.Let’s assume that when he squatted down before he jumped,his center of mass (just below his belly button) was about 14 inches lower than his normal standing position.Assuming that his hang time was 0.8 s,what was the force he exerted on the ground when he jumped?(Hint:First calculate the initial velocity when he jumped up.Then,consider how that velocity was generated from the squat position.Was there an acceleration involved?)

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骂人的都是SB 共回答了15个问题 | 采纳率86.7%
这次橄榄球比赛中,体重188磅的J.K接到了一个touchdown 传球(就是接球手接到传球并且带endzone 并且触地)传球手是G.S,J.K为了接住这个球,跳过了endzone左前方的对方防守.在这个跳跃过程中,J.K首先放低了身子以便起跳.我们假设J.K在跳前蹲了下来,他的重心(肚子底下左右)大约比他平时站姿的重心低14英寸.并且假设他离地的时间是0.8秒(我理解hang time是悬在空中的时间,也就是离地时间).请问他起跳时受到地面的压力是多大?(提示:首先计算他起跳时的速度.然后考虑如何从蹲着的姿势达到这个速度.有没有涉及到加速度?)
指考虑垂直方向,因为在空中只收到G力,且知道时间,所以起跳时的速度可以求得.
初速度是0,距离是14英寸,可求得加速度.vt平方减v0平方等于2as
然后这个加速度是188磅M,受到G力和地面向上压力合力的作用产生的,所以可以先求合力,减掉重力.
1年前
debbie_123 共回答了3个问题 | 采纳率
在这个过程中只有重力提供加速度,a=g,在空中末速度为0,根据加速度公式:a=(vt-v0)/t,即可得初速度。其它的和一楼讲的差不多,但是要假设这里的压力是不变的。
1年前

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英语翻译MacCrory's conversation was scintillating:she could neve
英语翻译
MacCrory's conversation was scintillating:she could never tell a story,chiefly because she always forgot it,and she was never guilty of a witticism,unless by accident.
没看懂,感觉scintillating应该换成sultifying.
emokele1年前3
车务之家 共回答了18个问题 | 采纳率83.3%
MacCrory谈起话来总是喜欢灵光一闪:她从来不会讲故事,因为她总是忘了讲.她也不会说什么俏皮话,但有时也有意外.
后边说她会忘东西,意思是她说话不会像讲故事那样连贯流畅,不会妙语连珠,但是偶尔会蹦出一两个好词,而scintillating意指闪烁的,冒火花的.恰好能和句子里“偶尔有点灵感的火花”对上,可以翻译为灵光一闪
这样你应该就能明白为什么不用stultifying了吧(sultifying是打错了吧?)和stultifying荒谬的、愚蠢的、乏味的这些意思相比较之下还是scintillating灵光一闪比较好