Serway & Jewett — The First Law of Thermodynamics: Problem 35.

Following a collision between a large spacecraft and an asteroid, a copper disk of radius \(28.0\text{ m}\) and thickness \(1.20\text{ m}\) at a temperature of \(850^\circ\text{C}\) is floating in space, rotating about its symmetry axis with an angular speed of \(25.0\text{ rad/s}\). As the disk radiates infrared light, its temperature falls to \(20.0^\circ\text{C}\). No external torque acts on the disk. (a) Find the change in kinetic energy of the disk. (b) Find the change in internal energy of the disk. (c) Find the amount of energy it radiates.