&gt; Well, F = ma was a bad example, I grant you. It&#x27;s actually a definition of what a force is, nothing more.<p>Although I would agree that it&#x27;s fair to say &quot;F=ma is a definition of what a force is&quot;, I think of it more as a law of physics than as a definition.<p>I would also add that Newton&#x27;s second law is more than merely the statement F=ma.<p>The original formulation is:<p>Law II: The alteration of motion is ever proportional to the motive force impress&#x27;d; and is made in the direction of the right line in which that force is impress&#x27;d. [1]<p>So in addition to stating what the word force means, the second law is also saying there are these things called forces which move things in a certain direction.<p>The way I think of F=ma personally, is that it means the laws of physics are associated with differential equations.  So for me, the statement F=ma implies a huge number of other things, since without <i>also</i> having made the assumption that the laws of physics can be described in terms of vector calculus, the definition of force is rather useless and uninteresting.<p>[1] <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Newton%27s_laws_of_motion#Newton.27s_2nd_Law" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Newton%27s_laws_of_motion#Newt...</a>