Typically, when solving physical problems, inertial reference frames (IRF) are used. IRF are reference systems in which Newton's first law is satisfied. It is in IRF that Newton's second and third laws are also satisfied. The work considers a number of problems of elementary physics, in solving which it is convenient to use non-inertial reference systems (NIRF). In this case, it is necessary to take into account the effect on the mechanical system of the so-called inertial forces. Detailed solutions to such problems are provided. It is shown that any real reference systems that we use when solving problems are, to one degree or another, non-inertial. Ultimately, the issue of taking into account their non-inertiality depends on the required accuracy of solving the problem. The paper presents solutions to four problems, for the solution of which it is advisable to use non-inertial reference systems. Moreover, the use of inertial reference systems to solve these problems leads to more cumbersome solutions. The list of such tasks can be significantly increased. We also note that when using non-inertial reference systems, many problems of dynamics, when solved, turn into problems of statics.