Date: Tue, 8 Oct 2002 14:20:10 -0400

Author: "Jason St. John"

Subject: Cavendish problems


Hi, folks.

We have a TA trying to set up a Cavendish balance, but he reports this

Once the sytem has settled to its equilibrium position without masses
nearby, placing a Pb sphere mass has the OPPOSITE effect of expected: the
nearest arm of the balance swings AWAY, and if permitted, it will swing
almost one hundred seventy degrees around. He's certain that he is
permitting transient oscillations to die down, and he's loathe to replace
the suspension wire, but that's the only place we can think to fix the

Those of you who are experienced with these: Does this sound familiar? Is
dark energy to blame or is there a fix?

Jason St. John 617.353.2634
Boston University Physics Lecture Demonstrations