本题目来源于试卷: gc textbook chapter 7 Linear Momentum,类别为 通用国际物理
[问答题]
We claim that momentum is conserved, yet most moving objects eventu/3( yjfg szp7l5hxlh 4ally s.h iffp- j6x cvqp4p31*o td4tlow down and stop. Epj41pi d3t-.v*fpfh qoxc4t6xplain.
参考答案: For momentum to be conserved, the system under
analysis must be “closed” – not have any forces on it from outside the
system. A coasting car has air friction
and road friction on it, for example, which are “outside” forces and thus
reduce the momentum of the car. If the
ground and the air were considered part of the system, and their velocities
analyzed, then the momentum of the entire system would be conserved, but not
necessarily the momentum of any single component, like the car.
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