单选题
图1-1-30所示平面力系P1、P2汇交在O点,其合力的水平分力和垂直分力分别为Px、Py,试判断以下Px、Py值哪项正确?()

- A.<img src="https://timg.fentiku.com/javaimportItems/7ccedf2d1910465fbfe69efadd4fae23/images/f120e.png" /><br/>
- B.<img src="https://timg.fentiku.com/javaimportItems/7ccedf2d1910465fbfe69efadd4fae23/images/f20cb.png" /><br/>
- C.<img src="https://timg.fentiku.com/javaimportItems/7ccedf2d1910465fbfe69efadd4fae23/images/f3269.png" /><br/>
- D.<img src="https://timg.fentiku.com/javaimportItems/7ccedf2d1910465fbfe69efadd4fae23/images/f424f.png" /><br/>
正确答案:C
