Nowadays, many researchers discovered various effective strategies in teaching physics, from traditional to modern strategy. However, research on physics problem solving is still inadequate. Physics problem is an integral part of physics learning and requires strategy to solve it. Besides that, problem solving is the best way to convey principle, theory, law, and formulation to students. This paper describes a new strategy in solving physics problems especially problems related to the application of Newton's second law. This strategy use a principle named system of total mass motion (STMM).