"It's a horizontal motion of two pieces of the Earth's crust on either side of a vertical crack in the Earth,"
VOA: standard.2010.01.13
The sense of going back and forth, no one of us on top, not correspondent in a vertical way, how things going down there.
这种来来回回的感觉,没有人是在高处,也没人在低处。
Time. Okay, pitch and time and pitch and duration, excellent, so those are the two dimensions of music and well, indeed we could even call them the axes of music because we tend to think of pitch on a vertical axis.
时间,音高和时间,或者是音高和时值,非常好,它们是音乐的两个维度,其实我们可以称呼它们为音乐的两轴,因为我们趋向于将音高放在竖轴上来考虑
For most of us, gravity acts this way, defines a vertical direction very naturally and the blackboard is oriented this way, so very natural to call that x and call that y and line up our axes.
对我们多数人来说,重力作用下,很自然地确定了竖直方向,而我们的黑板又是这个指向的,所以很自然地定出 x 轴和 y 轴,并标出我们的坐标系
In the meantime the Eiffel Tower is a wonderful way of showing the degree to which the vertical axis is virtual.
与此同时,埃菲尔铁塔,很好地向大家展示了,竖轴在何种程度上是虚拟的。
Excuse me. So what I'm going to do is, let's draw a picture that has S1 on the horizontal axis and S2 on the vertical axis.
好了,我们接下来来绘制图像,S1是横轴,S2是纵轴
For example, suppose you use vertical motion and you use y instead of x; and a would be g or -g; that's a particle falling down under the affect of gravity.
例如,假设在竖直运动中,你用 y 来代替 x,那么 a 就是 g 或者 -g,这就是一个受重力作用下落的质点
Quite often, it's natural to pick x and y in a certain way, because starting a projectile near the Earth, it makes sense to pick the horizontal as x and vertical as y.
我们经常会很自然地选取 x 轴和 y 轴,因为如果在地表附近做抛物运动,我们通常以水平方向为 x 轴,竖直方向为 y 轴
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