5. Which of the following is velocity? *
A. 20 m/s
B. 40 m/s east
C. 40 m
O D. 20 m

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