Force from Infinitely Long Cylindrical Magnet on Magnetic Dipole

[patm95]

Homework Statement

What is the force from an infinitely long cylindrical magnet on a magnetic dipole?

Homework Equations

M=Mz (given in problem)

The Attempt at a Solution

My argument for this solution that since the magnetization is in the z direction and the cylinder is infinitely long, there is no magnetization outside of the cylinder. I believe this is correct, but would like some feedback to make sure :) Thanks!

 

[WhoWee]

Perhaps you were expected to make calculations at varying/increasing lengths?