I've seen the simple experiment of dropping a neodymium sphere down through a copper or aluminum tube where it falls at less than g. The "Lenz Effect"
My question is:
Has there ever been an experiment when the NeoD sphere is tied to a string attached to a weight scale? Does the sphere weigh less at the midpoint inside of the tube than it does moving outside of it?
Someone may have done such an experiment, but it would be messy. It would be a lot easier to measure how long it takes the magnet to fall through the tube to get the same result.
Assuming the magnet falls with a uniform acceleration, since $$y=\frac{1}{2}at^2 \\ \rightarrow a=\frac{2y}{t^2}$$ Since you know the length of the tube $y$, and if you measure the time the magnet takes to fall through the tube $t$, then you can calculate the net acceleration of the magnet.
From this you can calculate the (net) force applied on the magnet, which is simply $$F_N=ma=\frac{2my}{t^2}$$ where $m$ is its mass. This force will obviously be smaller than the magnet's weight force.
