The Importance of R Circuit Modeling and Analysis

Andrés Cordero Muñiz

Resistances occur in everyday life and are not limited to the carbon resistors we commonly associate them with. Any device that consumes power can be modeled as a resistor and power sources can be modeled with a battery. In essence, you can model most scenarios of everyday life with a battery in parallel with resistors. Thanks to the easy to analyze nature of DC R circuits, it becomes trivial to measure values such as voltage, current and power.

For example, when you consider the accessories in your car, you get a circuit with a 12-V battery in parallel with resistances for the headlights, radio, each speaker, the ignition, etc. with switches. Everything is in parallel in order to receive the same voltage, and because this way if a light goes out, the rest of the accessories are not affected. If you can get the current provided by the battery, you can calculate the current that goes through your accessories and thus how many watts they consume, or if they specify watts, measure the current and calculate the resistance.

Another easy example is in your home. Things such as light bulbs, washing machines, computers, and your kitchen appliances have wattage ratings so in a model they also look as resistors, since they use up electrical energy and emit heat. By calculating the power draw, you can predict your future power bill and help conserve both energy and save your money.

For R Circuits there are many useful analysis tools, be it Kirchhoff’s Voltage and Current Laws, Current Divisor Equation, Voltage Divisor Equation, Parallel and Series Equivalencies, Wye-Delta transformations, etc. Thanks to Thevenin and Norton’s theorems, you can even model the net effect of a circuit with just a voltage/current source and a resistor!

In conclusion, R Circuits are the most basic type and the easiest to analyze, which is a good thing because they’re the most common model available, which is why Ohm’s Law is so essential in the world of circuits. Make sure you master the analysis of these before moving on to more complex circuit analysis!

Law of Inertia

Jose Luis Torres Pagan

According to Newton's First Law, or Law of Inertia a body can't change by itself its initial state, either at rest or in motion unless a force is applied on it. Suppose for a moment that our planet is the one who receives this force and cease to turn on itself. What would happen then in its surface? Would there be any change or everything would go normal?

The Planet Earth rotates at one speed and everything on its surface rotates at the same speed. If the Earth stops spinning we would still be rotating at that speed, by the effect of inertia. For example, if we drive a car in a speed of 50 km / h and stops suddenly we can't avoid a shift, unless we hold on with something or something support us in some way. Another example would be with the washing machines in our homes, you just have to see the washing clothes. Everything revolves around an axis, as in our planet, but it would not be hard to imagine what would happen if the axis is stopped suddenly. Certainly the clothes would still be in motion and would not stop just at the same time as their axis. That would happen in our planet if by "x" reason stops rotating, everything in the surface either be cars, oceans, animals and even humans could not prevent a displacement. But that effect would not be the same all over the planet, the closer we are to the axis of rotation, closer to the poles, the lower would be the effect on its surface. If we start to think about other consequences it would be that one part of our planet would be continually exposed to the sun, causing extreme temperatures and with it a host of problems. In contrast to the other side of our planet would be in the shadow, reaching very low temperatures that it would not be anything positive for the survival of our planet.

It is interesting when you think about the consequences that can occur and that’s when you realize that we live in a place under ideal conditions, we have our gravity, oxygen, and more. That even though we try to understand things, How, When and why? does not change the fact that this should be for life to take its own course. Well, with this thought I wanted to emphasize the importance of Newton's first law, the law of inertia in our planet and physics, because thanks to this is that we have understood many things that happen around us and things that maybe could happen.

Telescope

Michelle J Cruz Abril

We born with the knowledge that we live in a universe with planets, stars, bright galaxies, nebula and other fantastic things. We have to be grateful of all those scientist and philosophers that pass all his life making experiments and observations. Thanks to them we have all the information about our universe. But a big part of this knowledge it because the invention of the telescope. One thing that capture my attention about telescopes is because we have in Arecibo, Puerto Rico the world largest radio single aperture radio telescope and this make me feel more proud because it doesn’t care that we are a tiny island we have a lot of interesting things.

We can’t guarantee who invented the investigations says that Hans Lippershey was the inventor of this great artifact he fabricate lens and wasn’t well educated but with test he discover that with two lens, one of lens it was near the eye and this lens have to be divergent and other far of the eye and this one was convegent. Galileo Galilei (1564-1642), a mathematics professor in Italia, heard about this invention and constructs a telescope in less than a day. This was the beginning of the evolution of the telescope.

Galileo was fascinated about this new instrument and he comprehends more the functioning of the telescope because of that he can construct one that have an amplification of 30X but his range of visibility it was restrict. He discovers the craters of the moon, the four moons of Jupiter and the rings of Saturn. One year later he decide to publish a book named “the messenger of the stars” and it have only 24 pages but in it related all his observations in a clear and direct language with this book the reputation of Galileo goes up. He support the theory of Nicholas Copernicus but he have to denied because he go to a judgment and they said if you don’t deny it we put you in jail for the rest of your life. He live his last days teaching and searching new methods of shape lens.

Now we have different kinds of telescopes: optical, gathers and focus light of different parts and this kind have different branch; refractors, use lens; reflectors, have a concave mirror instead an objective lens and catadioptric which use a corrector lens and a concave mirror. Other is the radio telescope this function with directional radio antennas. The third kind is the X-ray and gamma ray they are used in high energy astronomy and the last one is the gravitational wave. 

Is amazing all things that the human has discovered but I would like to imagine what come next. The nature of the human being is explorer and we like to know all, investigate the unknown and look for new things. What would be the next great discover it could be you or somebody near to you we doesn’t know the future but I want to see it!