texan92 wrote:For people that have been using rigid rod pendulums, what were your masses of the the pendulum and rod? I was trying out a rigid rod and it doesn't seem to last more that a 100 seconds.
My rod is 20 g while the mass I'm using is 250 g. Is weight of the rod the issue or the contact b/w the rod and axle? I'm using a single ball bearing (3/8 in inner diameter, 5/8 in outer diameter) to put them together fyi.
The contact between the rod and axle is more likely to be the issue. The weight of the rod should not be all that significant, though it could be an issue considering how similar the two are in your pendulum.
As I recall, Primate was having similar problems with his rigid pendulum, I think the issue turned out to be the bearing he was using, but you could ask him.
We use an extremely heavy weight at the bottom of our pendulum, several kilograms. Adding weight to the bottom would probably help, but the best way is just to try and see.
Also, the cycloid idea has been on these forums pretty much as long as Time has been around, and nobody has ever reported making one. I think it's too much work for too little return.
Nationals 2010- Astronomy: 4, Physics Lab: 4, Picture This: 4, It's About Time: 10, Optics: 2
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