The weight of a train is a problem because even though the basic architecture of a railway reduces rolling friction between a wheel and the ground, it does nothing to reduce friction between the ...
Perhaps few physical concepts have received less attention relative to their importance than friction. Learning the 'effective' notions of static and sliding friction, students of mechanics can ...
Friction is a force between two surfaces that are sliding, or trying to slide, across each other. For example, when you try to push a book along the floor, friction makes this difficult.