A friend asked me to help her with a coursework question, I have pasted it below, I think a lot more information is required to even model this before working out freedoms. Am I missing something?

"A climbing stool in a library is used for reaching books on high shelves. It consists of a short cylinder on which a person can stand, mounted on 3 spherical bearings that touch the floor. By considering the constraints on the stools motion, determine how many freedoms the stool has, and describe how it can move."

Regards, Derek.