Re: what is a torsional pendulum?

A torsional pendulum works on the torque applied to the twisting wire.  
There is a restoring force or torque provided by the wire itself.  
Torsional pendulum wire is usually very stiff and made of many very tiny 
wires.  I used one once upon a time doing the Cavendish Gravitation 
Experiment back in college.  

The torsional constant is a property of the wire itself.  It was my 
experience that the linearity of response is a very narrow deflection ( or 
twist) of the wire.  There is really no way to change the torsional 
constant in a controlled way.

The natural frequency of oscillation is related to the natural frequency 
of oscillation of a spring.  It the SQRT(Restoring constant / moment of 
Inertia of the system).  The moment of inertia will be determined by the 
mass distribution about the axis of twist of the object attached to the 
torsion wire.

Sincerely,

Tom "Twister" Cull