A person is stretching by putting their arms straight over their heads and bending forward at their ankles until their hands are pushing against the wall in front of them. As they stretch, they keep stepping back from the wall, leaning further forward. The coefficient of static friction between their hands and the wall and their feet and the ground is 0.4. Each hand experiences the same normal force from the wall, and each foot experiences the same normal force from the floor, though the hand normal force and the foot normal force may not be equal. Their center of mass is at the middle of their total length (feet to hands). At what angle between the floor and their body do they slip?

Question

A person is stretching by putting their arms straight over their heads and bending forward at their ankles until their hands are pushing against the wall in front of them.  As they stretch, they keep stepping back from the wall, leaning further forward.  The coefficient of static friction between their hands and the wall and their feet and the ground is 0.4.  Each hand experiences the same normal force from the wall, and each foot experiences the same normal force from the floor, though the hand normal force and the foot normal force may not be equal.  Their center of mass is at the middle of their total length (feet to hands).  At what angle between the floor and their body do they slip?