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There is a new video regarding an old thread we had here:
https://www.physicsforums.com/threads/marble-spiralling-inside-a-cylinder.521152/
https://www.physicsforums.com/threads/marble-spiralling-inside-a-cylinder.521152/
With a contributing video from you, which inspired this one, if I may add ;).A.T. said:Steve Mould made a follow up video
I was a much younger man then. I don't even rmember the original thread. Guess I"ve got some reviewing to do...A.T. said:This is what I was trying to explain to @sophiecentaur and @DaveC426913 in the old thread:
https://www.physicsforums.com/threads/marble-spiralling-inside-a-cylinder.521152/post-3470602
The marble spirals inside the cylinder due to the combination of gravity and the shape of the cylinder. As the marble rolls down the inclined surface of the cylinder, it gains momentum and begins to spiral around the inner walls of the cylinder.
The main forces acting on the marble as it spirals inside the cylinder are gravity, friction, and centripetal force. Gravity pulls the marble downward, friction between the marble and the cylinder walls helps it maintain its spiral motion, and centripetal force keeps the marble moving in a circular path.
The marble spirals in one direction only due to the shape of the cylinder and the initial momentum of the marble. The inclined surface of the cylinder guides the marble to spiral in a specific direction, and once it starts spiraling in that direction, it continues to do so due to inertia.
The speed of the marble as it spirals inside the cylinder is determined by the angle of the cylinder, the initial velocity of the marble, the friction between the marble and the cylinder walls, and the diameter of the cylinder. A steeper angle, higher initial velocity, lower friction, and larger diameter will result in a faster spiral motion.
No, the marble cannot spiral indefinitely inside the cylinder. Eventually, the marble will lose momentum due to friction and gravity, causing it to slow down and eventually come to a stop. The length of time the marble spirals inside the cylinder depends on various factors such as the initial velocity and the smoothness of the cylinder walls.