A 13 g steel marble is spun so that it rolls at 164 rpm around the inside of a vertically oriented steel tube. The tube, shown in the figure, is 12 cm in diameter with µs = 0.8. Assume that the rolling resistance is small enough for the marble to maintain 164 rpm for several seconds. During this time, will the marble spin in a horizontal circle, at constant height, or will it spiral down the inside of the tube?

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