Why would I assume that the rest of the world is like my location?
That is a rightful question. That is why you need to travel. But let me explain you a bit about the history of mankind.
Let me explain you about where all the stuff we know come from (in a nutshell, while you can still imagine it)
IntroductionNowadays we got clocks, we got satellites, computers, all sort of stuff that help us determine something. But they all work on a simple entity. Numbers. We humans have developed a system to count things. The romans did using their style of numbers e.g. I, II, III, IV, V, VI, VII, VIII, IX, X, etc. In the history of mankind there were different civilizations with each their own mathematics. Some of their work is still in use today like the Pythagorean theorem, by the Ancient Greek philosopher Pythagorean. The history shows us different civilizations which used the 'zero' or nothing, before eventually getting brought to Europe by the Arabian mathematicians.
AgreementOur numbers today 1, 2, 3, 4, 5, etc, etc, etc all have a meaning, because we agreed that 1 means...well what 1 means now. A single thing. 2 means that there is twice that one thing, and so on. For the same reason we could have agreed on an order like 5, 1, 3, 2, 4. Or we could have had different symbols, just like the Romans had different symbols for their numbers. There is no fixed things that tells us what to do, but we simply agreed to use a single system.
Observating the world around us The same applies to time. Before any sense of time humans could see at their surroundings what time it was. Were the leafs falling of the trees? "Ah, it is that distinguishing thing we see that tells us we need to harvest our crops". It were the first notions of time. As mankind began to evolve and starting to invent and understand more of its surroundings, patterns became apparent. There is darkness, there is light. When there is light there is this big yellow thing moving across the sky. If it is dark we sometimes see a grey disk. At some point in history mankind named the big yellow thing the sun and at some point in history the returning of the sun everyday is another thing what we now call as 'day'.
The ancient Egyptians were worshipping the Sun as if it was a god they need to please. You do not want to make the God angry so it makes the sun disappear. This may have been a phenomena we now know as the solar eclipse and also at the end of every day the sun disappears out of sight, so you better be nice to the god so it will come back. That god was named "Ra" in ancient Egypt. But I digress.
The sense of time was born and there came tools to determine the time more accurately. There were sundials. Each day there is a point when the sun no longer rises above the horizon, but starts to descend again. That moment is what we now know as noon.
As mankind we just simply started to agree to means of measurement. Romans were able to measure the circumference of the earth using the stars and the amount of degrees from your point of view it stands up from the horizon. The Romans understood they were living on a spherical earth, so they travelled along the longitudes to get their measurement and then used maths to calculate the earth's circumference entirely.
How to calculate and know stuffSometimes you just need a small part to calculate the rest. For example we now have a standard saying a circle consists of 360 degrees. If I say 1 degree is equal to 1cm, then how much is the circumference of the entire circle? (Answer at the bottom).
As mankind began to explore the world maps were needed to navigate. Early maps were mostly inaccurate and incomplete. As the first Europeans start to sail the world, more maps were made. Using tools and simple means of measurement they were able to make much better maps. As they explored the earth they drew the maps. It is not like they had a map right away. Columbus did not even know about the existence of North America, but only thought he could also sail west instead of east to reach Asia. Unknown to him he discovered a whole new continent and at first he called the native americans Indians (from India, which you may know is in the east from a European perspective).
I could continue to talk on about all sorts of developments, but to make a much longer story shorter. The ways we measure things have been standarized and from there you just use the same equations and calculations to get your results. If you say 2+2 = 4, then the next time you have twice of two you will know it is 4 as well and not 5 this time, because you feel about it.
The same goes for all the maths in physics. They apply the same rules to everything, everyday. F = m × a
the a is calculated by A = m/s /s in which m/s is the speed in meters per second, the s...well you know now, stands for seconds.
the F in F = m × a = Force. This is expressed in Newtons. M stands for mass which is expressed in kilograms.
I hope you start to see where it is all coming from now? Sorry to make a long story out of it, but I hope you have a better understanding now where it is all coming from. The answer to the previous question I asked is 360 cm.