# Homework Help: Pendulum pivioting help

1. Mar 11, 2005

### explorien86

In my physics class we are working on an experiment that deals with energy (kinetic & potential) and right now we need to construct a swinging pendulum that has the least bit of friction to it possible. I have some basic concepts but he said it would cause to much friction that way. Would anyone here have any good ideas to make the pendulum swing with the least amount of friction?

2. Mar 11, 2005

### FredGarvin

In the immortal words of Fletch: "It's all ball bearings." You can get a relatively inexpensive roller or ball bearing to support the shaft that the pendulum swings on.

If you're not getting that in depth, tell us what your previous idea was and maybe we can expand on it.

3. Mar 11, 2005

### Chi Meson

To minimize air resistance, you want the densest material you can find for the bob. Most likely it would be lead. The string should be the thinnest and lightest combination that can hold the bob. Silk is a good option (available from a sewing/fabric shop. Sometimes simple is best: with a good metal clamp (clamped between two flat metal strips) the only friction is the interior friction of the silk thread bending. THis is very small.

Lead and silk; that's my suggestion.