lession 3.pdf - 3.1 Gravity and Forces Gravity is one of the universal forces that governs the motions of celestial bodies So how do we define a force

lession 3.pdf - 3.1 Gravity and Forces Gravity is one of...

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3.1 Gravity and Forces Gravity is one of the universal forces that governs the motions of celestial bodies. So how do we define a force ? We are all familiar with push and pull. This is an interaction that causes your body to accelerate. Acceleration is defined in terms of changing speed. When you accelerate your speed increases. When you decelerate your speed decreases. Newton was the first one to quantify the concept of force in his famous three laws. 3.1 重༒ʛ力和༒ʛ力 重༒ʛ力是ཀ支配天体运动的普遍༒ʛ力Ǐ量之ༀ一。 那么我们如何定义༒ʛ力呢? 我们都熟悉推拉。 这是ༀ一种相互作ཤ用,使您的身体加速。 加速度是根据变化的速度定义的。 当您加速时,速度会增加。 减速时,速度 会降低。 ཛྷ牛顿是他著名的三定ྋ律中第ༀ一个Ǐ量化༒ʛ力概念的༈人。 3.2 Force According to Newton’s laws a body continues in uniform motion, or at rest, unless a force acts on it. (Newton’s First Law). A force applied to a body causes it to accelerate by an amount given by the force divided by the mass of the body (Newton's Second Law). Acceleration is defined as the change in speed in a given time. Force is measured in units called Newtons. A force of one Newton causes a mass of one kilogram to accelerate with an acceleration equal to 1 metre per second per second. For completeness lets mention Newton's third law. It states that for every force there is an equal and opposite force. If you push the table with your hand, it will push back on you with this opposing force as hard as you are pushing on it. 3.2 ༒ʛ力 根据ཛྷ牛顿定ྋ律,除ྮ非有༒ʛ力作ཤ用于身体,否则身体将继续以匀速运动或处于静ཌ止 状态。 (ཛྷ牛顿第ༀ一定ྋ律)。
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施加到物体上的༒ʛ力使其加速,该༒ʛ力由该༒ʛ力除以物体的质Ǐ量得到(ཛྷ牛顿第༆二定 ྋ律)。 加速度定义为给定时间内的速度变化。 ༒ʛ力的单位是ཛྷ牛顿。 ༀ一ཛྷ牛顿的༒ʛ力使ༀ一公ང斤的质Ǐ量以每秒每秒 1 ྲྀ米的加速度加速。 为ຆ了完整起໅见,请提及ཛྷ牛顿第三定ྋ律。 它指出,对于每ༀ一个༒ʛ力都有相等且相反 的༒ʛ力。 如果您ཤ用༿手推桌༦子,它将以与您推桌༦子时ༀ一样༤大的反向༒ʛ力向后推。 3.3 Gravity Gravity is the universal force that acts between any pair of objects in the universe. It is a particularly important force in astronomy, because astronomical bodies such as planets, stars and galaxies have substantial gravitational forces. Whereas relatively small bodies that we know from our everyday life (like loaf of bread, a car, or even a house) are usually too small to exert a gravitational force that we can measure.
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