Frictional Force:Normal Force :: Applied Force:?

Frictional force is proportional to the normal force, just as the applied horizontal force on a body is proportional to the body’s weight. In other words, the ratio that gives the coefficient of friction (friction / normal) is analogous to the ratio that gives the coefficient of static friction (applied / weight). For a block on a horizontal surface, the normal force equals the block’s weight, so the applied force that keeps it moving is directly related to that weight. For example, a 10‑kg block has a weight of 98 N, and if a 49 N horizontal push is applied, the frictional force will be about 49 N when the coefficient of friction is 0. 5.