Find the moment of inertia Ia, xIa, xI_a, x of particle a with respect to the x axis (that is, if the x axis is the axis of rotation).

Which of the following best describes internal energy? a. the difference between the kinetic and potential energies of the particles in a system b. the sum of the kinetic and potential energies of the particles in a system c. the sum of the kinetic and thermal energies of the particles in a system d. the difference between the kinetic and thermal energies of the particles in a system