R And let the circle have a radius r.

这个圆环的半径是。

youdao

R You go around a circle which has radius r.

你绕圈的半径为。

youdao

R So if C is the circle, R is the disk of radius A.

就是C所包围的区域。，Well，，R，is，the，region，enclosed，by，C。,如果C是一个圆，R就是半径为a的圆盘。

youdao

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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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

耶鲁公开课 - 基础物理课程节选

That means, it can only be rattling around in a circle of radius R.

也就是说它只能,限制在一个半径为 R 的圆上运动

耶鲁公开课 - 基础物理课程节选