巧设坐标系简解抛体运动青海民院预科部宋文轩抛体运动中的某些问题求解过程比较繁琐，如果我们能灵活地设置坐标系，则可化繁为简，化难为易，达到巧解目的．现举例说明．例１山坡的倾角是３０°，大炮的仰角是４５°，炮弹出血度为４００米挪，从山脚发射的炮弹在山坡。... Cleverly designed coordinate system A simple solution to the projectile movement Some problems in the Song Wenxuan project of the Qinghai Civil Academy Preparatory Department are relatively complicated. If we can flexibly set the coordinate system, we can simplify everything and make it difficult to achieve it. Solution purpose. Here is an example. Example 1 The inclination of the hillside is 30°, the cannon’s elevation angle is 45°, and the cannon’s popping blood is 400 metres. The shells launched from the foot of the hill are on the hillside. ...