What do we mean when we say that momentumis a vector

The transfer of heat through the movement of a gas or liquid a. convection b. conduction c. radiation

The passing of heat through a material while the material itself stays in place. a. radiation b. conduction c. convection

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