- We have two identical metal sheets. One of them is rubbed with sand paper and the other with ordinary paper. The one rubbed with sand paper shines more than the other.
- While travelling on a rickshaw, you might have experienced that if the seat cover is very smooth, you tend to slip when brakes are applied suddenly.
- The friction between sand paper and metal sheet is very large, compared to that between the ordinary paper and the metal sheet. Thus, the sand paper is able to remove the outer dull layer from the metal sheet more effectively and makes it more shining.
- If the seat cover is very smooth then the friction between our body and the seat is very small. Therefore, when the brakes are applied we tend to slip.