You don't want to just ignore it, but in cases like that, it's usually a small fraction of the total.

你不能直接把它忽略掉,但在像这样的情形下，它一般是。

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It's true the net force is 0, but it doesn't mean you can ignore it.

所受的合力是 0,但是并不意味着你可以忽略它

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