Rotating disk with spring and mass · PhysicsBowl 2019 #12
Physics · mechanics
Problem
[Figure: TOP VIEW of horizontal disk with a spring and mass attached to a rod passing through its center]
A horizontal disk has a spring and a mass attached to a rod passing through its center. The spring has a spring constant of k and the attached mass is m. When the disk is not rotating, the equilibrium length of the spring is d. The disk is now angularly accelerated until it reaches a constant angular velocity of ω. At this angular velocity the length of the spring is now 2d. What is the angular velocity of the disk?
(A) dk (B) 2mk (C) m2k (D) k2d (E) 2kd