来自《耶鲁大学开放课程：基础物理 第9集 第9集》

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  that's the F·R·sin(θ), and add it up.
  就是 F·R·sin(θ) 然后求和
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  Again, when you do the torques,
  还有 当你计算转矩时
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  you've got to give it a sign.
  你得确定符号
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  If a torque tends to rotate a body counter-clockwise,
  如果转矩使物体逆时针方向转动
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  we will take it as positive,
  我们将其标记为正值
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  and if the torque tends to rotate a body clockwise,
  如果力矩使物体顺时针方向转动
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  we'll take it as negative.
  我们将其标记为负值
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  So, it's possible that in a given body,
  也有这种可能 已知一个物体
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  there could be torques trying to move it in different directions.
  它受到使它向不同方向运动的力矩
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  So, for example,
  比如说
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  in the simplest rigid body
  这个简单的刚体
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  made up of, say, two masses,
  两端带有质量