В России изменились программы в автошколах22:30
This would work even if the train on the left is somewhat heavier. So, it is possible for a train engine to pull cars that are more massive. But wait! There’s an even more important factor: A moving train car is rolling, not sliding. The wheel just touches the rail at one point and then rolls on to another point on the wheel. This is the magic of wheels: For the cars being towed, there is no longer any friction with the rails.
，这一点在wps中也有详细论述
Тайна из грязиУченые разгадали величайший секрет древних обитателей Сибири1 февраля 2019
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