Manhattan是考生在备考GMAT考试时必备的备考资料之一，在Manhattan阅读中对GMAT阅读考试的介绍非常详细实用，下面小编就为大家带来Manhattan阅读中文笔记-Chapter7(六)希望对大家的阅读备考有帮助。
Passage F: Sweet Spot
Though most tennis players generally strive to strike the ball on the racket's vibration node, more commonly known as the "sweet spot," many players are unaware of the existence of a second, lesser-known location on the racket face, the center of percussion, that will also greatly diminish the strain on a player's arm when the ball is struck.
In order to understand the physics of this second sweet spot, it is helpful to consider what would happen to a tennis racket in the moments after impact with the ball if the player's hand were to vanish at the moment of impact. The impact of the ball would cause the racket to bounce backwards, experiencing a translational motion away from the ball. The
tendency of this motion would be to jerk all parts of the racket, including the end of its handle, backward, or away from the ball. Unless the ball happened to hit the racket precisely at the racket's center of mass, the racket would additionally experience a rotational motion around its center of mass—much as a penny that has been struck near its edge will start to spin. Whenever the ball hits the racket face, the effect of this rotational motion will be to jerk the end of the handle forward, towards the ball. Depending on where the ball strikes the racket face, one or the other of these motions will predominate.
However, there is one point of impact, known as the center of percussion, which causes neither motion to predominate; if a ball were to strike this point, the impact would not impart any motion to the end of the handle. The reason for this lack of motion is that the force on the upper part of the hand would be equal and opposite to the force on the lower part of the hand, resulting in no net force on the tennis players' hand or forearm. The center of percussion constitutes a second sweet spot because a tennis player's wrist typically is placed next to the end of the racket's handle. When the player strikes the ball at the center of percussion, her wrist is jerked neither forward nor backward, and she experiences a relatively smooth, comfortable tennis stroke.
The manner in which a tennis player can detect the center of percussion on a given tennis racket follows from the nature of this second sweet spot. The center of percussion can be located via simple trial and error by holding the end of a tennis racket between your finger and thumb and throwing a ball onto the strings. If the handle jumps out of your hand, then the ball has missed the center of percussion.
生疏单词：
strike：击，打，罢工
vibration：振动，犹豫
node：节点，交点
racket：球拍，喧闹
percussion：打击乐器，振动，碰撞
bounce：反弹，跳
motion：运动，动作
jerk：猛拉，加速度
impart：给予，传授，告知
forearm：预先武装，准备
via：渠道，通过
长难句分析：
However, there is one point of impact, known as the center of percussion, which causes neither motion to predominate; if a ball were to strike this point, the impact would not impart any motion to the end of the handle.
known as the center of percussion作状语，对one point of impact进行描述，which引导定语从句，对击打中心进行解释，它不会导致支配性的运动，if引导条件状语从句，对另一请情况进行说明。
话题分类：自然科学
文章展开套路：问题解答型
作者态度：客观评价
文章脉络：
第一段：指出一个问题尽管大多数网球运动员一般努力打击球在球拍的振动节点,通常称为“最佳击球位置”,但许多球员都不知道另一个最佳的位置拍面。
第二段：对另一个最佳击球位置进行物理学角度的解释。
第三段：介绍另外的弹着点，被称为击打中心。
第四段：一个网球选手的打击方式可以检测给定网球拍上撞击中心遵循自然的第二个最佳击球点。更多相关内容请点击》两大普世性GMAT阅读法介绍。
答案：1-5: E A B D C
习题解析：
1. What is the primary message the author is trying to convey?
(A) a proposal for an improvement to the design of tennis rackets
(B) an examination of the differences between the two types of sweet spot
(C) a definition of the translational and rotational forces acting on a tennis racket
(D) a description of the ideal area in which to strike every ball
(E) an explanation of a lesser-known area on a tennis racket that dampens unwanted vibration
选项说明：
(A) 文章中作者没有提到想要改进网球拍的设计。
(B) 第一段提到了两种类型的击球点，但没有比较二者的不同。
(C) 文章只在第二段提到了对两种着力点的解释，没有概括文章的主要目的，范围太过狭窄。
(D) 尽管文中提到了求击打在最佳着力点的好处，但没有说是每一个球击打的最理想区域。
(E) 介绍了一个鲜为人知的球类击打点，可以减少不必要的振动。
2. According to the passage, a ll of the following are true of the forces acting upon a tennis
racket striking a ball EXCEPT
(A) The only way to eliminate the jolt that accompanies most strokes is to hit the ball on the center of percussion.
(B) The impact of the ball striking the racket can strain a tennis player s arm.
(C) There are at least two different forces acting upon the racket.
(D) The end of the handle of the racket will jerk forward after striking the ball unless the ball strikes the racket s center of mass.
(E) The racket will rebound after it strikes the ball.
选项说明：
(A) 第一段提到the center of percussion is only one of two sweet spots that minimize vibration这一振动点是另一个最佳击打点。
(B) 第一段的第三句这一影响会扭伤运动员的胳膊。
(C) 第二段描述了至少两种不同的着力。
(D) 第二段的第四句话unless the ball happened to hit the racket precisely at the racket's center o f mass, the racket would additionally experience a rotational motion。和第五句Whenever the ball hits the racket face, the effect o f this rotational motion will be to jerk the end o f the handle forward, towards the ball.
(E) 第二段第二句a racket will bounce backward after striking the ball; these words are synonyms for rebound.
3. What is the primary function served by paragraph two in the context of the entire passage
(A) to establish the main idea of the passage
(B) to provide an explanation of the mechanics of the phenomenon discussed in the passage
(C) to introduce a counterargument that elucidates the main idea of the passage
(D) to provide an example of the primary subject described in the passage
(E) to explain why the main idea of the passage would be useful for tennis players
选项说明：
(A) 主题思想是在第一段中体现出来的，第二段主要介绍了另一着力点的作用。
(B) 正确，和第二段的描述相符，it explains the mechanics of the second sweet spot in great detail.
(C) 第二段主要对撞击中心和中心作用力进行解释，没有进行反驳。
(D) 第二段主要是对两个新概念的解释，并不是提供具体的实例。
(E) 第一段和第三段提到让运动员知道这两个点是为了减少手臂受伤。
4. The author mentions “a penny that has been struck near its edge” in order to
(A) show how the center of mass causes the racket to spin
(B) argue that a penny spins in the exact way that a tennis racket spins
(C) explain how translational motion works
(D) provide an illustration of a concept
(E) demonstrate that pennies and tennis rackets do not spin in the same way
选项说明：
(A) 质量中心不会使球拍旋转，球击打在球拍上使其旋转。
(B) 文章中没有把a penny作为论据，而是用它举一个例子。另外exact属于极端词汇。
(C) 这个是关于回转运动，而不是平移运动。
(D) 正确，这是关于网球拍回转运动的一个例子，来对其进行解释。
(E) 这个例子是为了证明网球拍和硬币在受力作用下以相似的方式旋转。
5. Which of the following can be inferred from the passage?
(A) If a player holds the tennis racket anywhere other than the end of the handle, the player will experience a jolting sensation.
(B) The primary sweet spot is more effective at damping vibration than the secondary sweet spot.
(C) Striking a tennis ball at a spot other than the center of percussion can result in a jarring
feeling.
D) Striking a tennis ball repeatedly at spots other than a sweet spot leads to “tennis elbow.”
(E) If a player lets go of the racket at the moment of impact, the simultaneous forward and
backward impetus causes the racket to drop straight to the ground.
选项说明：
(A) 文中没有说，如果球员握住球拍杆以外的任何地方都会引起震动。
(B) 文中没有提到最佳击球点比二级击球点更能有效阻止震动。
(C) 文章介绍打球可能会导致胳膊受伤，但只要方式正确就会感到很舒适。
(D) 文中没有提到“tennis elbow”也没有提到哪种行为会导致受伤。
(E) 第二段简介提到运动员在手里的瞬间松开球拍的情形。但这种情形并不针对特定的着力点。
以上是关于Manhattan阅读中文笔记-Chapter7(六)的详细内容，希望大家也能从中受益，不断改进自己的备考方法提升备考效率，从而写出漂亮的文章获得满意的成绩。更多相关内容百利天下小编会持续为大家送上，祝大家都能早日梦圆名校。
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