77 Simple and Complex Machines-Low

Simple and Complex Machines Written by Ned Jensen

简单机器和复杂机器，作者:Ned Jensen

Introduction How do you eat soup? Did you know that a spoon is a tool? A tool is a simple machine. A machine uses energy to help us do work. Machines that have only a few parts are called simple machines. Some machines are made of many simple machines. A bike is a complex machine. In this book, you will learn how machines make work easier.

你怎么喝汤? 你知道勺子是一种工具吗? 工具是一种简单的机器。 机器利用能量来帮助我们做功。 只有几个零件的机器叫做简单机器。 有些机器是由许多简单的机器组成的。 自行车是一种复杂的机器。 在这本书中，你将了解到机器如何使工作更容易。

Do You Know? Animals use tools, too! Apes use sticks to get ants. Sea otters use rocks to open clamshells. In science, work has a special meaning. It means making something move. To move something, you use force. If you push hard to move something, you use a lot of force. If you use a lot of force, you do a lot of work, If you push only a little to move something you use a little force. If you use a little force you do a little work. When you do work, you also move something over a distance. If you move something a short way, you do a little work. If you move something a long way, you do a lot of work.

你知道吗?动物也使用工具!猿用棍子抓蚂蚁。 海獭用石头打开蛤壳。 在科学中，工作具有特殊的意义。 意思是让某物移动。 要移动某物，你要用力。 如果你使劲推某物，你用了很大的力。 如果你用了很大的力，你做了很多功，如果你只用了一点力来移动某物，你用了很小的力。 如果你用一点力，就做一点功。 当你做功的时候，你也移动了一段距离。 如果你移动一个物体很短的距离，你就做了一点功。 如果你移动一个东西很长一段距离，你做了很多工作。

Machines often help you move something (do work) using less force. But there is a trade-off. When you use less force, you have to move the thing farther. The total amount of work stays the same.

机器通常帮助你用更少的力移动东西(做功)。 但这是一种权衡。当你用更少的力时，你必须把东西移动得更远。 总功保持不变。

Types of Simple Machines These are the simple machines you will read about in this book.

简单机器的类型这些是你将在本书中读到的简单机器。

Inclined Plane The ramp is a simple machine. It is also called an inclined plane. A ramp helps people move heavy objects up or down. Movers use ramps. It is easier to slide a box up an inclined plane than to lift a box straight up. Using a ramp takes less force. If you use a longer inclined plane to move a box up the same height, you need less force. But remember, you also have to push the box farther.

斜面是一种简单的机器。 它也被称为斜面。 坡道可以帮助人们上下移动重物。 搬运工使用坡道。在斜面上滑动一个盒子要比直接举起一个盒子容易。 使用坡道省力。 如果你用一个更长的斜面来移动一个箱子到同样的高度，你需要更少的力。 但是记住，你还必须把盒子推得更远。