Problem 19.

A dancer is standing on one leg on a drawbridge that is about to open. Before the drawbridge starts to open, it is perfectly level with the ground. The dancer is standing still on one leg. What is the x component (horizontal component) of the friction force?

Solution:

Since there is no motion of the dancer and there is no possible motion of the dance, then the x-component (horizontal component) of the friction force is 0.