Gravity And Other Forces

GRAVITY and other Forces

重力和其他力

Which force matters most? Welcome to the world of forces. I'm a force myself. You'll find out about me on page 27. Before that, though, you're going to meet some of my rivals. Forces are pushes and pulls. Without us, nothing would move at all. Forces make the world go round. 1 Getting up would be impossible (instead of just difficult). 2 Running out of the house couldn't happen. 3 You wouldn't be able to push down on your bike pedals. 4 Your bike brakes could not pull you to a stop. 5 Even just sitting up needs help from forces. The other forces and I work together all the time, but we're not friends exactly. They all think they're too important. In fact, some of them think they're the MOST important forces in the world. They're going to tell you what makes them so special. Then, at the end, we'll decide which actually is the most important force.

哪种力量最重要？欢迎来到力量的世界。 我自己就是一股力量。你会在第27页找到我。 在那之前，你要去见我的几个对手。 力就是推和拉。 没有我们，什么都动不了。 力量使世界运转。 起床将是不可能的（而不仅仅是困难）。 2跑出房子是不可能的。 你不能踩下你的自行车踏板。 你的自行车刹车不能让你停下来。 即使只是坐起来也需要力量的帮助。 其他势力和我一直合作，但我们不是朋友。 他们都觉得自己太重要了。 事实上，他们中的一些人认为他们是世界上最重要的力量。 他们会告诉你是什么让他们如此特别。 然后，在最后，我们将决定哪个是最重要的力。

Gravity The force that is everywhere I gravity, am a mega-force! I am everywhere and I'm part of every single object. I am a pulling force. Every single object has gravity, but it is stronger in objects containing a lot of matter. A mouse contains a tiny amount of matter. An elephant contains more matter than a mouse. Objects have to be really VERY big before you notice their gravity. Even an elephant is too small. Planets, though, are definitely big enough. LOTS of matter= big gravity Gravity stops you from floating off into the air... ...and keeps AIR from floating off into space. Gravity also makes walking uphill hard work and gymnastics scary. Out in space, some black holes have SO much gravity that they pull together whole galaxies of stars. So, I keep your feet on the ground, bring you air to breathe, and even hold together your galaxy. I MUST be the most important.

无处不在的引力，是一种巨大的引力！我无处不在，我是每件物品的一部分。 我是一个拉力。每一个物体都有引力，但在含有大量物质的物体中，引力更强。 一只老鼠含有少量的物质。 一头大象所含的物质比一只老鼠多。 物体必须非常大，你才能注意到它们的引力。 即使是大象也太小了。 然而，行星绝对足够大。 大量的物质=巨大的重力重力阻止你漂浮到空中… …并防止空气漂浮到太空中。 重力也使上坡变得困难，体操变得可怕。 在太空中，一些黑洞的引力非常大，可以将整个星系的恒星聚集在一起。 所以，我让你脚踏实地，给你呼吸空气，甚至把你的星系连在一起。 我必须是最重要的。

Weight Gravity's best friend Gravity and I work together ALL the time. I'm the force gravity makes by pulling on an object. This means I change depending on how strong gravity is. On Earth, the force of gravity is 1g (the 'g' stands for gravity'). Imagine this: when you stand on scales they say 40 kg. Here on Earth you are also rubbish at the high jump. On the Moon, gravity is much weaker: just 0.1654 g up there, the scales would say 6.6 kg. Your legs would still be able to jump with just as much force, though. With only the Moon's weak gravity pulling you down, you would be excellent at the high jump.

重力和我一直在一起工作。 我是重力对物体的拉力。 这意味着我的变化取决于重力的强弱。 在地球上，重力是1g （g代表重力）。 想象一下：当你站在秤上时，秤上显示40公斤。 在地球上，你们跳高也是垃圾。 在月球上，重力要弱得多：在月球上只有0.1654克，秤上的重力应该是6.6公斤。 不过，你的腿仍能以同样的力量跳跃。 只有月球微弱的引力把你往下拉，你跳高的时候就会很出色。

The truth about gravity Gravity and weight are such big-heads! Actually, gravity is really weak. I'll explain... Fact about gravity: no.1 Unless an object is massive, you can't even feel its gravity. Fact about gravity: no.2 Even Earth's gravity can easily be beaten. For example, using simple machines is a way to defeat gravity. Ramps make climbing upwards, against gravity, much simpler. Ramps are a kind of simple machine called an inclined plane. Pulleys are another kind of simple machine. Using a pulley can make it easy to lift objects that would otherwise be too heavy. Fact about gravity: no.3 Gravity gets weaker the further away you go. So to make Earth's gravity weaker, all you have to do is... Climb a really, really tall mountain. Go up in a weather balloon. Weather balloons do not actually carry human passengers.) Go 400 km up to the International Space Station, where you won't feel gravity at all.

关于重力的真相重力和重量是如此的大！实际上，引力非常弱。 我将解释……关于重力的事实：第一除非一个物体质量很大，否则你甚至感觉不到它的重力。 关于重力的事实：第二即使是地球的引力也很容易被击败。 例如，使用简单的机器是一种战胜重力的方法。 坡道使向上攀登，对抗重力，变得简单得多。 坡道是一种简单的机器，叫做斜面。 滑轮是另一种简单的机械。 使用滑轮可以很容易地抬起原本太重的物体。 关于重力的事实：no.3你走得越远，引力就越弱。 所以，要想减弱地球引力，你所要做的就是…… 爬一座非常非常高的山。 乘气象气球升空。 气象气球实际上并不携带人类乘客。)到400公里外的国际空间站，在那里你根本感觉不到重力。

Friction Grr- WHO says another force is more important than me? I'll fight any other force you can name! I'll push and push at it until it gives up! I'm a pushing force between two objects that are sliding across each other. (Trying to slide, anyway: sometimes I make them stop!) This makes me brilliant at slowing things down. My skills at slowing things down are very useful when going too fast on your bike. I release heat as a side-effect. The more friction there is, the more heat is released. When you have cold hands, the friction of rubbing them together warms them. Experts can even use friction to start a fire. The brake pad now touching wheel causes friction, so the wheel slows down. I do all sorts of slowing down or gripping-on jobs. That definitely makes me the most important force on the street!

谁说另一种力量比我更重要？ 我会和任何你能想到的力量战斗！我要推啊推，直到它放弃！我是两个相互滑动的物体之间的推力。 （不管怎么说，我试着滑动：有时我会让他们停下来！）这让我很擅长放慢节奏。 当你骑自行车跑得太快时，我减慢速度的技巧非常有用。 我的副作用是发热。 摩擦力越大，释放的热量就越多。 当你的手冰凉时，相互摩擦会使它们温暖起来。 专家们甚至可以利用摩擦点火。 刹车片现在接触车轮引起摩擦，所以车轮减速。 我做各种各样的慢节奏或抓紧的工作。 这绝对使我成为街上最重要的力量！