This. Physics is a field of science, unlike math. They're dealing with models that keep on changing. Newton's model of F=ma is generally close enough for most t

This. Physics is a field of science, unlike math. They're dealing with models that keep on changing. Newton's model of F=ma is generally close enough for most things, but breaks near the speed of light. Following the model solely would give you the false idea that speed of light is just yet another number.