___________________ | | | | | | | | 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: 當細繩還沒被剪掉的時後兩條繩的張力各為 mg 剪掉以後 左繩的張力應該要大於mg 但是在 剪掉右繩的"瞬間" 左繩的張力應要等於 mg 因為如果大於 mg 那右邊質量傳遞力的速度就是 無限大 不合理 不知道我這樣的想法對不對? 這題我想了好久都沒一個好的解法 這題目可以用 Lagrangian Dynamics來解嗎? 我該從那下手? 請版上的高手指教 !! --

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