相对运动

解释什么是相对运动：一个物体看起来的速度和方向，取决于观察者自己怎样运动。可以用日常生活中的例子来说明，比如火车和汽车从旁边驶过。

Explain relative motion — how the apparent speed and direction of an object depends on the observer's own motion — using everyday examples such as trains and cars passing

学习证据 / Evidence

• 解释为什么两列同方向、同速度行驶的火车，在车上的乘客看来好像是静止的。
• 计算两个物体彼此靠近或彼此远离时的相对速度。
• 解释为什么描述运动时参考系很重要。

• Explains why a train moving at the same speed in the same direction as another appears stationary to passengers on that train
• Calculates relative speed when two objects move towards or away from each other
• Explains why the frame of reference matters when describing motion

评估问题 / Assessment

如果{{name}}在一列火车上，另一列火车从同一方向更快地驶过，{{name}}能解释为什么那列火车看起来速度很慢，即使它实际上正以很高的速度行驶吗？

If {{name}} was on a train and another train passed going the same direction but faster, could they explain why it looks slow even if it's actually travelling at high speed?