3. In Einstein's model of solids, each atom in the crystalline lattice is an independent 3D harmonic oscillator undergoing vibrations around its equilibrium position. Using this model and assuming that the classical description is valid, A. Estimate the heat capacity (C=d(E)/dT) of a US penny, which you can assume consists entirely of Zn and whose mass is m=2.5 g. B. Estimate how much the internal energy of a US penny fluctuates (i.e. estimate its (AE) at room temperature. Compare it with the average energy of the penny. C. The assumption that the atoms are decoupled from one another does not seem very realistic. In an effort to improve upon Einstein's model you decided to introduce an additional Hookean spring connecting each pair of adjacent atoms. Would your answer to Parts A and B change for this new model?