22 Get Moving!

Get Moving! by LAURA MAWER

行动起来!作者:LAURA MAWER

Chapter 1 Push and Pull Can you see a force? No, you cannot. But you can see what a force does. Forces make things move. The stronger the force, the faster or farther something moves. There are two kinds of forces. They are push and pull. A push moves something away from you. A pull moves something toward you. We use push and pull forces every day. Throwing a ball is a kind of push. If you throw the ball hard, it will fly fast in the air.

第一章推和拉你能看到力吗? 不，你不能。但你可以看到力的作用。 力使物体运动。力越强，物体移动得越快或越远。 有两种力。 他们是推和拉。推力会把某物从你身上移开。 拉力使某物向你移动。 我们每天都在使用推力和拉力。 扔球是一种推。 如果你用力扔球，它就会在空中飞得很快。

Gravity and friction are forces that pull. Let's say you throw a ball to your dog. Your dog races to catch the ball. He misses it. The ball drops to the ground. What force pulls the ball to the ground? Gravity does. When the ball hits the ground, it may roll. What would make it stop? The answer is friction. Friction happens when two things touch each other. Let's say one of the things is moving, and the other is still. Friction pulls on the moving thing to stop.

重力和摩擦力都是拉力。 假设你把一个球扔给你的狗。 你的狗跑去接球。 他想念它。球掉到地上。 是什么力把球拉到地面上? 重力。当球碰到地面时，它可能会滚动。 什么能让它停下来?答案是摩擦。 当两个物体相互接触时就会发生摩擦。 假设其中一个物体在运动，另一个静止。 摩擦力使运动的物体停止。

Chapter 2 Tools That Push and Pull Bats are tools that push. Think about it. What happens when a bat hits a baseball? The bat pushes the baseball away. If the ball is hit lightly, it may not go far. But if the ball is hit hard, it could go out of the park!

第二章推和拉的工具蝙蝠是推的工具。 想想看。当球棒击中棒球时会发生什么? 球棒把棒球推开。 如果球被轻轻击中，它可能飞不远。 但是如果球被重重地击中，它可能会跑出球场!

Hammers are tools that push, too. A park worker might fix a broken park bench with a hammer. The worker could use the hammer to hit a nail into the wood. The hammer would give the nail a big push. Then the bench would be safe to sit on again. A hammer could also be used to pull. The worker could pull out a nail. He could use the claw end of the hammer.

锤子也是推动的工具。 公园工作人员可能会用锤子修理破损的公园长椅。 工人可以用锤子把钉子钉进木头里。 锤子会给钉子一个很大的推力。 然后又可以安全地坐在长凳上了。 锤子也可以用来拉。 这个工人可以拔出一颗钉子。 他可以用锤子的爪端。