There are sometimes three ways to solve a mechanics problem. One is to use the laws of motion. One is the force method, that is Newton's three laws. The last is the energy method or the workenergy theorem.
One must first begin by mastering the first method mentioned abv, then the 2nd then the third.
The third method sometimes solves problems faster, however, to understand physics indepth, it is imperative one masters the other methods first. Reason being that the workenergy theorem is nothing but some basic calculus done upon Newton's 2nd law, and new terms defined, viz., energy and work.
