The subject that I like

If you had read my other post, probably you will notice that I like physics.
But, in the beginning, I like math, i always saw them like a game, when you realize an equation, when you "play" with the numbers and how math can help you in certain way to ... i don't know, buy bread, distribute a certain amount of something and  in some basics economic things.
With this in mind, when I met physics, I said " OH! Another way to use math and I can use it to know useless things that anybody cares" or something similar.
In this classes I always pay attention to the teacher, and when he explain a "formula" and what is good for. Then, when I went to Preu, I love how the teacher sees the nature, or something like that, he always had an "easy " point of view of how you can find the formula given above. Of something so easy, obtain a complex calculation, like the mass of the Earth or, with more knowledge, obtain the gravitation constant. Of course this potentiate when I went to the university, last year.
Obviously, this equation works in a theoretical world when, almost everything, are negligible. But it still giving a valid result, and this thing of modeling the life, predicting what is going to happen in a certain amount of time or obtain unknown information with a few data, it surprises me. Making me interested in physics.