일반물리학 1 — Rotation: Problem 33

33 (a) A uniform 2.00 kg disk of radius 0.300 m can rotate around its central axis like a merry-go-round. Beginning from rest at time $t = 0$, it undergoes a constant angular acceleration of $30.0 \text{ rad/s}^2$. When is the rotational kinetic energy equal to 2000 J? (b) Repeat the calculation but substitute a ring of the same mass and radius and assume that the spokes have negligible mass.