4.3 Conservation of Linear Momentum

Center of Mass Motion

Before now, we have typically considered the center of mass of a system as stationary when no external forces act. However, the center of mass can also have its own velocity, known as the velocity of the center of mass.

This velocity remains constant unless an external net force acts on the system.

Important Equation: ${v_{cm} = \frac{\sum p_i}{m_{tot}}}$

${v_{cm}}$ is the velocity of the center of mass

${p_i}$ is the momentum of each object in the system

${m_{tot}}$ is the total mass of the system