对一道典型力学问题的思考

Thinking about a typical mechanical problem

分析了用悬线将一重球悬挂于天花板下,然后拉重球下方的另一悬线,此后两根悬线谁先断裂这一典型力学问题.结果表明,当拉动悬线的速度v小于某一临界速度Vc时,球上方悬线先断裂;当v>Vc时,则情况较为复杂,具体是上方悬线断裂还是下方悬线断裂取决于悬线能承受的极限张力Fm;当v>>Vc时,选取具有合适的Fm值的悬线,可使得球下方的悬线先断裂.

A typical mechanical problem is analyzed in this paper.A heavy ball is hanged below the ceiling by a rope,and another rope is tied at the bottom of the ball.If the end of the rope moves at a certain velocity,which rope will snap first.The results show that when the moving speed v is less than a certain critical speed Vc,the rope above the ball snaps first.Which rope snaps first when the speed exceeding Vc is decided by the maximum tensile force that the rope can sustain.The rope under the ball snaps first when the speed v>>Vc.