Consider a gas in a container; the random motion of molecules causes several collisions with the walls. During collisions, each molecule exerts a force on the container's walls, which is the source of the pressure exerted by the gas. If all gas molecules have the same magnitude of velocity, the interaction with the wall in the x-direction for small time intervals results in a change of x-component of velocity and momentum. If the number of molecules per unit volume remains uniform, the number of collisions for certain area and change in the total momentum during the small interval can be determined. Applying Newton's second law, the pressure exerted by the gas depends on the molecule's mass, speed, and number of molecules per volume. Considering the isotropic condition, the average velocity of a gas molecule is related to the velocity components and is equal to three times the velocity of a component. By substituting and comparing with the ideal gas equation, the average translational kinetic energy of n mole of gas is determined.