Acopper rod at 25°c is 1.5 m long. how long would it take a sound to move through the rod from one end to another? how would i do this?

Consider an insulating crystal, made up of layers of atoms. what form would you expect the temperature dependence of the phonon heat capacity to approach at extremely low temperatures if the interlayer coupling is i)very strong (rigid coupling), and ii) very weak. explain.

Ihave a density of 1.61g/cm^3 and a mass of 28g. find the missing value

According to newton’s law of universal gravitation, which statements are true? as we move to higher altitudes, the force of gravity on us decreases. as we move to higher altitudes, the force of gravity on us increases. as we gain mass, the force of gravity on us decreases. as we gain mass, the force of gravity on us increases. as we move faster, the force of gravity on us increases.