rotating magnetic top is floating above a magnetic base. Suppose the base is resting on a "weight" scale. With the top floating the scale reads w. At the end of the video the top falls onto the base where it rests in contact with the base. The weight scale reads a) w c) w d) it depends on the orientation of the top on the base.

Question

rotating magnetic top is floating above a magnetic base. Suppose the base is resting on a "weight" scale. With the top floating the scale reads w. At the end of the video the top falls onto the base where it rests in contact with the base. The weight scale reads
a) <w b) >w c) w d) it depends on the orientation of the top on the base.

egenriether · Answer

the weight would not change.  realize that in order for the base to provide an upward force on the top, it needs to make an equal downward force on the scale its sitting on.  Whether the top is pushed upward by the magnetic field or the normal force due to being at rest on the base does not matter.  Note that the reason the base and top do not pass through one another when it comes to rest on the base is the electrical forces of the atom.  So when the top floats, a magnetic field keeps it from falling to the center of the earth.  When it is at rest on the base, electrical forces keep it from falling to the center of the earth!

anonymous · Answer

That makes a lot of sense! so the answer is c) then?

egenriether · Answer

yep.