第9课

Unit 3

第三单元

Motion of an object

物体的运动

The planes are flying, the trains are running.

飞机在飞，火车在跑，

The high mountains slipped away from under our feet,

高山从我们脚下悄悄溜走，

......

The sun rises and the moon sets, and the stars turn.

日出月落，斗转星移，

Who is in motion?

谁是运动的？

Who is stationary?

谁是静止的？

Let's work on it together.

我们一起研究吧。

9 Stillness and motion 静止和运动

What objects in life are at rest? Which objects are in motion?

生活中，哪些物体是静止的？哪些物体是运动的？

By motion of an object, we mean that this object has changed its position with respect to another object.

我们所说的物体的运动，是指这一物体相对于另一物体来说，它的位置发生了变化。

Who is stationary in a car that is moving?

正在行驶的车内，谁是静止的？

Whose position has changed?

谁的位置发生了变化？

Let's do a simulation experiment.

做个模拟实验吧。

To describe whether an object is moving or at rest, an object must first be identified as a standard, and this selected object is called a reference.

要想描述物体是运动的还是静止的，必须先确定一个物体作标准，这个被选定的物体叫参照物。

Let's describe stationary and motion.

我们来描述静止和运动。

Sun

太阳

Earth

地球

Moon

月球

You have to choose a good reference yo!

可要选好参照物呦！

Check the information to understand the operation of synchronous satellites.

查阅资料，了解同步卫星的运行情况。