This video focuses on the conservation/balance of linear and angular momentum. The linear and angular momentum for particles is explained first. Newton’s law for linear momentum changes and Euler’s law for angular momentum change are discussed. The idea of linear and angular momentum is extended from particles to continuous bodies. The center of mass, which can be written in two ways, is introduced.
The quantities defined in previous videos are used to write out the balance of linear and angular momentum equations, including the rate of change of linear and angular momentums. We also consider the expressions for external force and external moment. The rate of change of linear momentum is equal to the external force; the rate of change of angular momentum is equal to the external moment.