Friction is a force that is dependent on external factors. Following are the two factors on which friction depends:
| 1. On the nature of the two surfaces that are in contactFriction is dependent on the smoothness or roughness of the two surfaces that are in contact with each other. When the surface is smooth, the friction between the two reduces as there is not much interlocking of irregularities. While the surface is rough, friction increases. |
| 2. On the force that is acting on these surfacesFriction increases when the force is applied along with the irregularities. |