The first thing about a wheel is that it rolls as it moves rather than slides. This greatly reduces friction. Why?
Difficulty: Easy
When the axle of a wheel is pushed, the force of friction between the wheel and the ground at the point of contact provides the reaction force. The reaction force acts at the contact points of the wheel in a direction opposite to the applied force. The wheel rolls without rupturing the cold welds. That is why the rolling friction is extremely small than sliding friction.
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