* Friction: Friction is the force that opposes motion between two surfaces in contact. Rough surfaces have more points of contact and irregularities, creating higher friction. Smooth surfaces have fewer points of contact and less irregularity, leading to lower friction.
* Example: Imagine pushing a box across a carpet (rough) versus pushing it across a polished floor (smooth). You'll need to exert more force on the box to overcome the friction from the carpet.
In summary: A smoother surface results in less friction, which means less force is required to move an object.
