You can actually calculate the angle at which that blood hit your surface."

VOA: special.2010.05.05

Another question is: at what angle should you fire your projectile so it will go the furthest?

另一个问题是以多大角度抛出,物体能飞得最远

耶鲁公开课 - 基础物理课程节选

So-- if you don't feel comfortable doing it, don't do it-- what I'd like to do now is as following: Take your thumb and your middle finger and create as much as possible a 90 degree angle.

感觉不舒服的，就不要做，希望按下面的指示做：,让你的姆指和中指,尽可能形成一个直角。

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