- #31
slow
- 93
- 16
thermia said:
Have you ever tried, say as instructional entertainment, to formulate basic mechanics without the variable called time? For example, instead of taking length, mass and time as fundamental magnitudes, take strength, length and speed. The first challenge you will find is to propose an operating procedure to measure speeds. The procedure to measure forces gives a little less problem. And the procedure for measuring length has been known since ancient times. If you do it, if you make observations and prepare data tables, in a short time you will see in the tables reasons to assume some hypothesis that inspire confidence. They inspire you at least within the limitations of your experiments. And you will also understand without much complication the need to define a function dependent on the force, the path traveled and how aligned or oblique the force is with respect to the path traveled. That is to say that defining work will be an obvious necessity. You will arrive intuitively and easily at the theorem of mechanical work and kinetic energy. And you would arrive even if you had never gone through a physics classroom or read anything about Newton. You would formulate a basic mechanics without introducing the time variable. And if after all that you want to establish a time definition, you will notice that there is no unique way to formulate a function ## t ## that satisfies the definition of time. The definition and function that you decide to adopt as a time formulation have no univocal relationship. You will also see that within the limitations of the experimental setup you have done, your tables of experimental values give a constant result when you divide the data of one column by the data of another, within the same row. That result does not change from one row to the others. So it is not wrong to assume that this quotient is a constant of each body that you have used in the tests. It is not wrong to suppose that to each body corresponds a value of that quotient, being that value independent of the speed, the force and the other conditions. That value is the mass and, only within the limitations of your essay, you have reason to consider it constant. The constant mass hypothesis complicates the form of the time function, whichever option you choose to formulate it. We could say more, but a button is enough to show.
The good thing about this didactic game is to understand that physics is not a fruit that nature has made and is hanging from a plant and is completely done, waiting for us to simply see it and take advantage of it. Physics, from its most basic beginnings, is a product that is made by mixing observations with logic, logic with supposed ideas (hypothesis), hypothesis with voluntary decisions to define magnitudes and functions, in a partially arbitrary way. The game of building basic physics without the definition of time teaches us to be prudent, austere and in favor of everything that helps avoid dogmatism.
Regarding time, it is an abstract function and it is impossible to build an instrument that directly measures time values. Everyone obtains data that is entered into the variables of the time function and gives a result that, conventionally, we decided to accept.
