genralz Posted January 2, 2009 Share Posted January 2, 2009 Hi, I have to construct a yo yo with the GREATEST amount of time to reach the location below(9.38m+/-0.025m) its starting point. Basically it has to be the slowest yo yo not exceeding 60 minutes. Basic Guidelines: *No battery or motor powered yo yo's *.5m*.5m*.5m size limitation before it descends *Total mass must be more than 0.5 kg but less than 1.0 kg full guidelines here: http://teacherweb.com/MA/WatertownHigh/Duggan/photo5.stm (under Yo-Yo Rules) Please post all ideas, thanks! Link to comment Share on other sites More sharing options...
Klaynos Posted January 2, 2009 Share Posted January 2, 2009 So, what makes a yo yo fall? How can you provide a force against that? Link to comment Share on other sites More sharing options...
Phi for All Posted January 2, 2009 Share Posted January 2, 2009 .5m size limitation before it descends, there's a clue. Some way to get it to make itself bigger once it starts to descend would help slow it down. If the "bigger" part provided drag it would be even better. Link to comment Share on other sites More sharing options...
genralz Posted January 2, 2009 Author Share Posted January 2, 2009 yes both great points, but i want the simplest yo yo to make, simple yet slow and making it grow is a tip but it doesn't require it to. Link to comment Share on other sites More sharing options...
Phi for All Posted January 2, 2009 Share Posted January 2, 2009 You can make the simplest yo-yo, or you can make the yo-yo with the GREATEST amount of time to reach the location below(9.38m+/-0.025m) its starting point, but you can't do both. Why do you want the simplest? Link to comment Share on other sites More sharing options...
Mr Skeptic Posted January 2, 2009 Share Posted January 2, 2009 Does the yo-yo have to go back up? If not, increase drag. Otherwise, concentrate the mass at the farthest from the center that you can as allowed by the size limit. Link to comment Share on other sites More sharing options...
npts2020 Posted January 2, 2009 Share Posted January 2, 2009 It seems to me a good way to increase the time is to have it do a series of bounces while descending where after the last bounce you are at the end of the string. I also thought about some sort of ratchet mechanism but am unsure how you could do it without making the yoyo stop (against the rules). Link to comment Share on other sites More sharing options...
genralz Posted January 3, 2009 Author Share Posted January 3, 2009 no the yo yo does not have to come back up, just descend and i want to make it simple so that if it doesn't work than i can start with a new one. Mr. Skeptic how you recommend me to increase drag? and npts, bounce? how can I construct those within the boundaries of the rules? Since I cannot use glues or gels to alter the rope. Link to comment Share on other sites More sharing options...
Mr Skeptic Posted January 3, 2009 Share Posted January 3, 2009 Then, make it as light and big as possible, and the opposite of streamlined. Eg add sheets of paper from the axis to the outside. Link to comment Share on other sites More sharing options...
iNow Posted January 3, 2009 Share Posted January 3, 2009 What about some sort of pulley system? I'm thinking that you could translate the spin into slower revolutions on the yo-yo through a few gears of different sizes... Link to comment Share on other sites More sharing options...
npts2020 Posted January 3, 2009 Share Posted January 3, 2009 Increse drag with a flywheel of some kind that expands with speed and drags on the string. You should be able to set it at nearly any speed from zero to free fall. I will have to think about how to get it to bounce all the way down the string but it seems to me you could rig a ratchet mechanism of some kind to make it do that instead of stopping. Link to comment Share on other sites More sharing options...
iNow Posted January 3, 2009 Share Posted January 3, 2009 Yeah, npts... that's exactly what I had in mind... like some sort of transmission or differential gearing... I just am not sure how to implement it. Link to comment Share on other sites More sharing options...
Mr Skeptic Posted January 3, 2009 Share Posted January 3, 2009 But will the gears help if the whole thing rotates? Link to comment Share on other sites More sharing options...
Phi for All Posted January 4, 2009 Share Posted January 4, 2009 Then, make it as light and big as possible, and the opposite of streamlined. Eg add sheets of paper from the axis to the outside.It has to start out at no more than .5m but can grow. It needs some kind of telescoping arms forced out by the spin. Link to comment Share on other sites More sharing options...
Mr Skeptic Posted January 4, 2009 Share Posted January 4, 2009 IMO it shouldn't spin fast enough to force out telescoping arms. Link to comment Share on other sites More sharing options...
npts2020 Posted January 4, 2009 Share Posted January 4, 2009 IMO it shouldn't spin fast enough to force out telescoping arms. Only if it spins at the rate of the yoyo and isnt geared down. (think about a grandfather clock that uses weights) I haven't decided on the bounce part yet but am thinking it may require more than one spindle or an offset one. Link to comment Share on other sites More sharing options...
swansont Posted January 4, 2009 Share Posted January 4, 2009 Note: another discussion here Link to comment Share on other sites More sharing options...
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