This particle is constantly changing its direction, but it therefore has an acceleration and the acceleration, we have shown here, is pointing towards the center.

这个质点恒定地改变它的运动方向,因此它具有加速度,而且这个加速度,我们前面也讲过了,指向圆心

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It's good to have a vector pointing in the radial direction of length one.

所以引入这么一个模长为 1,方向沿圆心向外辐射的矢量作用很大

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You have the same acceleration directed towards the center.

同样是直接指向圆心的加速度

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This is the acceleration directed toward the center.

加速度方向指向圆心

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When a particle moves in a circle, it has an acceleration towards the center of this size, v^2 over R.

当一个质点在圆周上运动时,它有一个指向圆心的加速度,v^2 / R

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That means the acceleration is pointing towards the center of the circle and it has a magnitude a.

也就是说加速度,始终指向圆心,其模长为 a

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It tells you when a particle moves in a circle, it has an acceleration in a negative R direction, namely directed towards the center.

它告诉你当一个物体在圆周上运动时,它有一个在 -R 方向的加速度,也就是说是直接指向圆心的

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At each point, er is a different vector pointing in the radial direction of length one.

矢量 er 在每一点处都不同,方向都从圆心指向该点,模长为1

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v^2 / R is the acceleration directed towards the center of that circle.

^2 / R 就是指向那个圆心的加速度

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Whenever you see a particle moving in a circle, even if it's at a constant speed, it has an acceleration, v square over r directed towards the center.

只要看到质点做圆周运动,即使是匀速圆周运动,也存在一个加速度,大小为 v^2 / r,方向指向圆心

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If you want to write it as a vector equation, you want to write it as v square over r minus-- I want to say that it's pointing in the direction toward the center.

如果要写出矢量方程,就应该写成 -v^2 / r,也就是说,方向就向圆心

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