Rolling spool: String on spool is pulled at various angles.

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(A)Mechanics - A+55: Rotational Dynamics

The Rolling Spool. Case 1: Spool with string wrapped around inner cylinder. String pulled at different angles. As string is pulled up, the spool rolls to the left. Case 2: At a certain angle, as the string is pulled, the spool rolls in place. Case 3: As the string is pulled to the right, the spool rolls to the right. Inner diameter = 94mm Outer diameter = 203mm
UCB Index: 
A+55+5
PIRA Index: 
1K10.30
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Demo Picture: 

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Comments

James Little

Thu, 10/01/2015 - 09:53

This demo requires a lot of supervision as it can roll. Make sure that you instruct the participant to experiment gently and keep on eye on what they're doing! Ask them to describe features of the spool and how they'd expect a solid cylinder to behave with a rope being unwound from it. After they've talked about what they expect let them gently experiment. If necessary lead them told discover the mode where the spool rolls forward, back, and spins in place. As always when you present a demo make sure you ask the participants questions before you demonstrate and after. Think about the concepts involved beforehand; having a friend ask you questions about it can be very revealing as to if you understand it well or not. Whenever you ask a question count to five (or at least three) in your head waiting for an answer before you stay anything else.