本题目来源于试卷: gc textbook chapter 7 Linear Momentum，类别为 IB物理学
[问答题]
A Superball is dropped from a height h onto a hard5d pcnkmnm58ivrp3(fcf 4f10 stex )-pqv j(/29 nsro,lz 9vtali/fnex5 el plate (fixed to the Earth), from which it rebounds at very nearly its original speed. (a) Is zv//nlft q 9r j v2l),5xxnp(sei9oa-the momentum of the ball conserved during any part of this process? (b) If we consider the ball and Earth as our system, during what parts of the process is momentum conserved? (c) Answer part (b) for a piece of putty that falls and sticks to the steel plate.
参考答案: (a) The momentum of the ball is not conserved during any part of the process, because there is an external force acting on the ball at all times – the force of gravity. And there is an upward force on the ball during the collision. So considering the ball as the system, there are always external forces on it, and so its momentum is not conserved. (b) With this definition of the system, all of the forces are internal, and so the momentum of the Earth-ball system is conserved during the entire process. (c) The answer here is the same as for part (b)
本题详细解析:
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