Question

A bolt of mass 10 g is welded tangentially to the end of a torsion spring with a 2.1 cm radius. The spring is attached to the center of the board with the bolt resting horizontally at equilibrium directly above the center of the spring.

(a) The board is rotated 79⁰, at which time the bolt points vertically. What is the stiffness of the torsion spring.


(b) If the board is rotated to 90⁰, then what is the angular extension of the spring in radians?
[Assume the extension is smaller than 15⁰.]

Answer 1