静力学中通过引入力的将力的矢量计算转化为标量计算。
查看答案
平面汇交力系平衡的解析法是力系中的各个力向两个坐标轴上投影的分别。
若平面汇交力系的各力矢作用线都平行于x轴，则该力系只需满足一个平衡方程∑Fix = 0，力系即平衡。
A. 对
B. 错
You are about to go onstage to give a presentation. Though you have prepared well, your hands have started to shake and your knees are feeling weak. What do you do?
A. Call off the presentation.
B. Take a deep breath, visualize your success and hold onto the lectern when you are onstage.
C. Go get a glass of water or something small to hold onto.
D. Quickly find someone else to give your presentation.
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