Does a solid, like a night stand, vibrate macroscopically because the atoms and molecules that make up the solid vibrate?

Question

We know particles that make up solids vibrate, but do the solids vibrate themselves because of that? Like a structure or object like a night stand, does that night stand vibrate macroscopically because the particles are vibrating microscopically ?

Answer 1

Hi Hailey, The answer is, "No," for the simple reason that momentum is always conserved. For example, if Molecule A moves to the right and Molecule B moves to the left as a result of vibration of the AB system, the average momentum of the two molecules remains unchanged. In classical mechanics, the only way that the momentum of an object can change is if a net force is applied to it. Even in the AB system, Molecule A accelerates due to the force applied by B, and vice versa. The center of mass of the system does not vibrate.