___________________ | | | | | | | | O------------O Two masses (m) are connected by a thin rod of length L. The whole system is suspended by two strings at both ends as shown in the folloing diagram. What is the tension of the left string acting on the mass-rod system immediately after the right string is cut? a) Consider the case of a massless rod. Solve the problem by using two different methods. (Certainly, make sure you get the same answer!) b) Extend one of your calculations to the case that the mass of rod also equals to m, which is uniformly distributed. ___________________ | | | _ <-- cut at t=0+ | | | O------------O 我自己的想法是: 当细绳还没被剪掉的时後两条绳的张力各为 mg 剪掉以後 左绳的张力应该要大於mg 但是在 剪掉右绳的"瞬间" 左绳的张力应要等於 mg 因为如果大於 mg 那右边质量传递力的速度就是 无限大 不合理 不知道我这样的想法对不对? 这题我想了好久都没一个好的解法 这题目可以用 Lagrangian Dynamics来解吗? 我该从那下手? 请版上的高手指教 !! --

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