# Frictional forces on banked curve

I am quite confused when I consider the frictional force for an object moving around a banked curve.

I understand that the direction of friction changes from pointing up the slope to down the slope as the centripetal acceleration increases, as the horizontal components of the normal and frictional forces result in the centripetal force.

However, my understanding is that both the gravitational force and normal force experienced by the object remain constant. How can this be the case if the direction and magnitude of the frictional force (with its horizontal and vertical components) changes with velocity?

I created a diagram below that illustrates my understanding of the forces present when the velocity of the object on the banked curve is zero, small, and very large (diagrams 1, 2, and 3 respectively). For the forces in the y-direction to remain balanced while the frictional force changes, the y-component of the normal force should also be changing, which doesn't make sense to me.

Is there something that I am missing here, or is the normal force actually changing with velocity?

• For the diagrams, the folowing notation is used: graviational force $F_G$ , normal force $N$, frictional forces $F_f$, $F_f'$ and $F_f''$, and centripetal forces $F_c$ and $F_c'$. The horizontal and vertical components of each of the forces is denoted by $x$ and $y$ subscripts. Dec 28, 2021 at 21:12
• You might find this site helpful: hyperphysics.phy-astr.gsu.edu/hbase/Mechanics/carbank.html Dec 28, 2021 at 21:28