美國網友說：
Many of us have gotten rock chips, but how many of us understand how those pesky rocks hit our windshield? A common misconception is that the car in front of us throws rocks "backward" and hits the following car's windshield. A rolling tire cannot throw a rock backwards. A tire is a rolling object, thus every point along the tire is moving forwards. There is no force going in a backwards direction. Only direction part of a rolling object can go is a combination of up or down, and forward.
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