A 10 g steel marble is spun so that it rolls at 150 rpm around the inside of a vertically oriented steel tube. The tube is 12 cm in diameter. Assuming that the rolling resistance is negligible enough for the marble to maintain 150 rpm for several seconds. During this time, will the marble spin in a horizontal circle, at constant height, or will it spiral down inside the tube? Prove your answer. Take coefficient of static friciton to be 0.8.