A disk (radius, r = 5 m, mass, m = 50 kg) is resting on a perfectly frictionless surface. Two students, Morrigan and Samael, are standing at the outer edge, opposite from each other. Both Morrigan and Samael have masses, mh, = 50 kg (they are both at r = 5 m). At exactly the same time, both Morrigan and Samael start walking counter-clockwise at v = 1 m/s relative to the disk. What is the angular speed of the disk?

What belongs in the areas marked x and y? x: the internal energy of a piston system increases as heat is added and rises to a cool area y: as thermal energy is added to a container, some of the energy is lost to the environment x: as thermal energy is added to a container, some of the energy is lost to the environment y: the internal energy of a piston system increases as heat is added and rises to a cool area x: a cold spoon placed in hot liquid gets warmer y: thermal energy is converted to light energy x: thermal energy is converted to light energy y: a cold spoon placed in hot liquid gets warmer