Direct Current

Last week in class we learned about Electric Current, Resistance, and Power. We learned more basic definitions of this unit: voltage, current, and resistance. A voltage is the amount of work that each charge will do as it goes through a circuit. It can also be thought of as the amount of push on the charges. A current is the number of charges passing a point per second. It is also known as the rate of flow of charge (I). Resistance is the opposition to flow of charge; also any application that asks the charge to do and will slow it down. One thing that I began to understood was what we learned about circuits. We learned that for a system to work, it needs to be in a circuit. Without potential difference or voltage charges will not flow. The different types of currents are direct and alternating currents. A direct current is where charges flow one way. An example that I related to was my laptop charger. As I was doing my homework, my computer began to run low on battery, so I grabbed my laptop charger and plugged it into the wall. Because of the direct current my laptop began to charge. 

   

Voltage & Capacitance

This week we learned about capacitance, and we can find capacitance by using the formula C=(Eo)(A)/(d). Eo is the permitivity of free space and has the constant 8.85x10^-12 c2/nm, A is the area, and d is the distance of separation in meters. The units of capacitance is known as Farands (F), Coulombs/Volts. We learned that with this, we can find the magnitude of the charge between two plates. We also learned more about voltage. Voltage is also known as Electric Potential or Electric Potential Difference. It's units are volts or Joules/Coulombs. We learned that electric potential is only highly dangerous when there is a lot of charge. An item may have a lot of volts but it is not dangerous unless it has a lot of charge. I am starting to understand this unit a little better. 

Electric Potential

This week we began to learn about the difference between Electric Potential and Electric Potential Energy. Electric Potential is measured in volts (Joules/Coulombs). Electric Potential could also be referred to as voltage or Electric Potential Difference. In class, we did an example using batteries and small light bulbs. It was shown that the batteries have a positive and negative side. Electric potential was determined by the electric potential energy per quantity of charge. Although the voltage of an item may be high, the shock may not be so "shocking" depending on how charged the object is. As said in class, an object can have a voltage of 100,000 volts but it wouldn't create a huge effect if the object has a really low charge. 

Electric Charges Continued.

Last week we continued learning about Electric Charges. Some of the concepts that we have learned in class are somewhat difficult for me to grasp. It makes it a lot easier when I am able to compare it to real life situation or situations around me. One of the things we learned in class is that opposites attract and like charges repel. That concept is pretty much relatable to a lot of people. Me and my friends are alike in so many ways but there are things about us that are unique and different others. We are more likely to hang out with each other than hang out with anyone else. I am glad that we are learning about Electric Charges. I am learning more about how and why things are attracted or not attracted to each other.

Electric Charges

This week we started a brand new unit. We started on Chapter 19: Electric charges, forces, and fields. We revisited some of the things that we learned back in Chemistry. Protons, electrons and neutrons are some of the things that we will need to know for this unit. An electron is a stable subatomic particle with a charge of negative electricity. It is found in all atoms. A proton is a stable subatomic particle occurring in all atomic nuclei, with a positive electric charge equal in magnitude to an electron. A neutron is a subatomic particle of about the same mass as a proton however without an electric charge. This week in class we also learned about conductors and insulators of of electric charges. Conductors are items that transfer their electrons easily. They also conduct heat very well. An example of a conductor is metal. Insulators are items that want to hold on to electrons. Some examples of insulators are wood, rubber and cardboard. We also learned about the Charge Force Law. The Charge Force Law states that like charges repel one another, for example, a positive charge and a positive charge or a negative charge and a negative charge. A neutral charge and a neutral charge does not repel, there is no effect. Also, unlike charges will attract. For example, a negative charge and a positive charge. 

Semester 1 Reflection

 I never really liked science even before I started physics. It never interested me at all. I found it hard to pay attention in my science classes because nothing really interested me. I guess that is why I don't succeed as well as others in science classes. This year, I tried to get into what we were learning in physics class. We learned a lot in just the first semester of class. I learned more about Newton's three laws of motion. Newton's first law of motion states that every object in a state of uniform motion tends to remain in that state of motion unless acted upon by an external force. Newton's second law of motion states that acceleration is produced when a force acts upon a mass. The greater the mass the greater the force needed. Newton's third law states that for every action there is an equal and opposite reaction. I also learned about the conservation of different things. I learned about the conservation of momentum. The conservation of momentum principle states that when a system of masses is subject only to internal forces that masses of the system exert on one another, the total vector momentum of the system is constant. I also learned about conservation of energy. The conservation of energy principle states that energy neither be created or destroyed it can only change forms. These are only a few things that I have learned so far in Physics. I am looking forward to learning more in the upcoming semester. 

*Energy (missing)

Energy is the capacity of a physical system to perform work. Work is defined as the integral of the force over a distance of displacement. There are different types of energy that we learned about this week in class. We learned that kinetic energy is  the energy possessed by a system or object as a result of its motion. We also learned that potential energy is the ability of a system to do work due to its position or internal structure. In class, we also learned about the conservation of energy. According to the law of conservation of energy, the total energy of a system remains constant, though energy may transform into another form. A rollercoaster is a perfect example of how energy is used. 

The SI unit of energy is the Joule (J) or Newton-meter (N*m). This is also the SI unit of work.