67 Force and Motion-High

Force and Motion Written by Ned Jensen

力与运动Ned Jensen著

Introduction Each word above describes how objects can move. Some things move in a straight line, such as a ball rolled to you along the ground. When you kick the ball into the air, it flies in a curved path and then bounces on the ground until it stops. A merry-go-round revolves in circles, while lightning strikes in a jagged path. Motion is everywhere, and it's vital to life. Think of how your heart's movement keeps blood flowing throughout your body! In this book, you will learn what makes things move, stop, change direction, and change speed.

上面的每个词都描述了物体如何移动。 有些东西是直线运动的，比如一个球沿着地面滚向你。 当你把球踢向空中时，它会沿着弯曲的路径飞行，然后在地面上反弹，直到停下来。 旋转木马绕着圈转，而闪电则在参差不齐的路径上打转。 运动无处不在，它对生命至关重要。 想想你心脏的运动是如何保持血液在你全身流动的!在这本书中，你将了解是什么使事物移动、停止、改变方向和速度。

Motion Needs a Force In order to make something move, a force is required. Lifting, pushing, and pulling are all types of forces, and those forces come from countless sources. Sometimes a person can provide the force. If you lift a stack of books, push a broken-down car, or pull on a rope in a tug-of-war game, you are the source of a force.

运动需要一个力为了使某物运动，就需要一个力。 举、推、拉都是各种类型的力，而这些力的来源是无数的。 有时一个人可以提供力量。 如果你举起一堆书，推一辆抛锚的汽车，或者在拔河比赛中拉一根绳子，你就是一种力量的来源。

Machines can also produce a force to move objects. The power of a huge engine can produce enough force to propel a massive rocket into space. A car's smaller engine makes its wheels spin, moving the vehicle down a road. Motors in cake mixers, fans, and blenders use electrical force to make things move. Nature can act as a force, too. For example, breezes make leaves dance in the treetops. Ocean waves make boats bob up and down. Forces deep underground can cause earthquakes that make the ground tremble and destroy buildings, bridges, and highways.

机器也能产生力来移动物体。 巨大发动机的动力可以产生足够的力量推动一枚巨大的火箭进入太空。 汽车的小型发动机使车轮旋转，使车辆在道路上行驶。 蛋糕搅拌机、风扇和搅拌机中的马达利用电力来推动物体运动。 自然也可以作为一种力量。 例如，微风使树叶在树梢上跳舞。 海浪使船只上下颠簸。 地下深处的力量会引起地震，使地面颤抖并摧毁建筑物、桥梁和高速公路。

The Laws of Motion Much of what we know about motion comes from experiments and observations made by scientists hundreds of years ago. The Englishman Isaac Newton is especially famous in this regard. You may have heard of him as the man who was sitting under a tree when an apple fell and hit him on the head. The story goes on to tell how this event led to his theory about gravity, the invisible force that causes things to fall toward the ground. Actually, Isaac wasn't hit on the head by a falling apple— that's a myth. But over time, he observed that objects always fell down toward the ground. These observations, combined with his curiosity, drove him to study gravity. Sir Isaac Newton (1642-1727) Isaac Newton was born on Christmas Day in Woolsthorpe, England. He lived on a farm with his grandmother. He had little interest in becoming a farmer and chose instead to study math and science at Trinity College, which is part of the University of Cambridge in England. At age 27, Newton conducted experiments with light and was the first to suggest that light was actually made up of all the colors. He eventually became one of the most famous scientists of all time!

运动定律我们对运动的了解大部分来自数百年前科学家的实验和观察。 英国人艾萨克·牛顿在这方面尤其著名。 你可能听说过他，当时他坐在树下，一个苹果掉下来砸在了他的头上。 这个故事继续讲述了这一事件如何导致了他关于引力的理论，引力是一种导致物体落到地面的无形力量。 事实上，艾萨克的头部并不是被掉落的苹果击中的——这是一个神话。 但随着时间的推移，他观察到物体总是朝着地面下落。 这些观察，加上他的好奇心，驱使他去研究重力。 圣诞节那天，艾萨克·牛顿出生于英国伍尔索普。 他和祖母住在农场里。 他对成为一名农民没有什么兴趣，而是选择在英国剑桥大学的三一学院学习数学和科学。 27岁时，牛顿进行了光的实验，并第一个提出光实际上是由所有颜色组成的。 他最终成为有史以来最著名的科学家之一!

Newton's First Law of Motion Isaac Newton is best known for writing three laws of motion that explain how all things move. The first part of Newton's first law says that an object at rest will remain at rest unless a force acts upon it. For example, your bike will stay parked where it is unless someone or something moves it. The second part of the first law states that an object in motion will continue in motion at the same speed and in the same direction unless a force acts upon it. So if your bike is rolling, it will continue moving just as it is until you pedal faster, coast, brake, or turn. If a force, such as a headwind, pushes from the opposite direction of the bike's motion, it will slow the bike or stop it completely. If a force, such as side wind, is applied to one side of the moving bike, the bike will change direction. Word Wise The word law often means a rule made by a government that people must obey. In science, a law is a statement about results that always occur under certain circumstances.

牛顿的第一运动定律艾萨克·牛顿最著名的是写了三条解释万物运动的运动定律。 牛顿第一定律的第一部分说，静止的物体将保持静止，除非有一个力作用在它上面。 例如，你的自行车会一直停在原地，除非有人或什么东西移动它。 第一定律的第二部分指出，运动中的物体将继续以相同的速度和方向运动，除非有一个力作用在它上面。 因此，如果你的自行车在滚动，它会继续运动，直到你踩得更快、滑行、刹车或转弯。 如果一个力，如逆风，从自行车运动的相反方向推动，它将使自行车减速或完全停止。 如果一个力，比如侧风，施加在移动的自行车的一边，自行车就会改变方向。 法律这个词通常是指政府制定的人们必须遵守的规则。 在科学中，定律是关于在特定情况下总是发生的结果的陈述。