【简答题】设系统由 n 个物体组成,其中 n 1 个物体受平面任意力系作用, n 2 个物体受平汇交力系作用, n 3 个物体受平面平行力系作用, n 4 个物体受平面力偶力系作用。则系统能够列出的独立的平衡方程的最大数目 K 为 ( )。A. n 1 +n 2 +n 3 +n 4 B. 2n C. 3n 1 +2n 2 +2n 3 +n 4 D. 3n
【简答题】One day an old man is selling a big elephant. A young man comes to the elephant and begins to look at it slowly. The old man goes up to him and says in his ear, “ Don’t say anything about the elephant...