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Reflections

Here is where you will post your reflections on each chapter/unit/topic we cover.

Energy

posted Jan 28, 2011, 12:54 PM by Vanessa Cordeiro

The two main types of energy that I remembered most easily from last year were gravitational potential (mgh) and kinetic energy. (1/2 mv^2).  I also remembered working on conservation of energy problems.  I had forgotten the equations for work and power and their units  but it did not take long to relearn those. I do think that looking at the world in terms of conservation laws is easier than in terms of dynamics (forces), mostly because they do not include vectors, which makes everything more complicated.  The rules for conservation laws are more simple and straightforward, and although both make sense, topics such as energy are less complicated and have less room for making mistakes.  When organizing energy problems, i always write down what is given and what i am looking for to keep me on track.  Also although i tend to go straight to using the equations, when the problems start to get more difficult making a table usually helps. 

Fluids

posted Jan 28, 2011, 12:44 PM by Vanessa Cordeiro

Doing this unit almost completely on my own was daunting at first but it was not as bad as i thought it might be.  The packet we got had most of the information and practice problems that we needed and supplemented with the online resources, it was enough to get through.  I do not think there need to be any more resources, since if anyone needs more information there is unlimited info online.  The day we spent on going over the chapter in class was probably the most useful since it cleared up any questions i had and gave me a better understanding.  I did not use the book at all for this chapter: too wordy.  The webassign was, as always, very helpful since it includes various types of problems that you have to work through until you can get the correct answer.  The video tutorials and solutions are helpful when i get tired of reading or when listening to the tutorials just make things more understandable.  Also the video solutions are useful because sometimes it is hard to follow written solutions, like how you get from one step to the next.

Momentum

posted Jan 28, 2011, 12:32 PM by Vanessa Cordeiro

The main thing i remembered about momentum from last year is that when the external net force on a system equals zero momentum is conserved, as stated in the law of conservation of momentum.  I had trouble remembering how to actually solve momentum problems but once we started going over them this year, it started coming back to me.  Conservation of momentum laws definitely make understanding the world easier because things work out more simply when momentum is conserved.  Also you do not have to worry about what happens to any momentum that it lost or gained.  The momentum chapter was not so bad considering it went well with kinematics, the equations were simple and of course because of the conservation laws.  

Circular Motion

posted Jan 28, 2011, 12:21 PM by Vanessa Cordeiro

Circular and linear motion are very similar.  In fact kinematics equations and circular motion equations are almost identical. The difference is that for kinematics the equations include displacement, velocity and acceleration but in circular motion the equations include angular displacement, angular velocity, and angular acceleration.  Also the units use radians in place of meters.  Centripetal acceleration is the rate of change of tangential velocity, caused by a centripetal force, which keeps an object moving in a circular path.  I do agree that centripetal force is not the best term to use because it is not a force on its own, it is actually the net total of forces that create a circular motion.  This also means that centripetal force can not actually be included in a free body diagram.  I felt that this chapter was fairly easy since we had already done the kinematics chapter, which is very similar. 

Forces and Newton's laws

posted Jan 28, 2011, 12:06 PM by Vanessa Cordeiro

Many people have trouble understanding how forces truly work.  One of the common misconceptions about forces is that when two objects interact the larger object exerts a larger force.  This, as we learned is untrue.  According to Newton's third law of motion, if one object exerts some amount of force on an object, the second object applies an equal but opposite force.  Newton's laws of motion include two others.  His first law states that an object at rest tends to remain at rest and an object in motion tends to stay in motion unless acted on by an outside force. Newton's second law states that F=m*a. So acceleration depends directly on force and inversely on mass. The part about forces that i found difficult last year was splitting up forces in different directions, such as when an object is on an inclined plane rather than on flat ground.  It was hard because it gets messy and i found it easy to make mistakes but this year after doing those kinds of problems so many times i find it much easier. 

Electromagnetism

posted Jan 28, 2011, 10:51 AM by Vanessa Cordeiro

In everyday life electromagnetism is very useful.  For example with the creation of an electromagnet can be used to start up a car or to power other electronics.  Electromagnets are also used in microphones, televisions, speakers, and computer hard drives.  I thought the hardest part to figure out in this chapter was the rules for when a current is created and which way it flows.  The right hand rule was helpful, although at first it confused me more. The lab was easy to perform but it was hard to understand how to explain what had happened and what that means. 

Ohm's Law and circuits

posted Nov 14, 2010, 9:13 PM by Vanessa Cordeiro   [ updated Nov 14, 2010, 9:21 PM ]

I think that it was ok to do the review mostly on our own because we had already gone over it last year.  Doing the review problems at home and the webassign was enough review to refresh my memory on the subject.  Still the circuits can be tricky and it took me a while to fully understand how they work.  I feel like the mathematical part of this chapter was easier than the "common sense" part because it takes a better understanding of circuits to figure out what is going on within them than to just plug some numbers into given equations.  I still feel like i could use some more practice on the "common sense" part, so I can feel more comfortable answering those types of questions. 

Electric Potential and Energy

posted Nov 14, 2010, 9:01 PM by Vanessa Cordeiro   [ updated Nov 14, 2010, 9:12 PM ]

In my opinion this unit was more difficult to understand than the electric fields and forces unit, but by the time of the test I feel like I had a good grasp on this unit.  Doing the webassign and follow along notes helped me practice for the test.  I do not this the two units should be combined because although they are similar it would be too much information to take in all at once.  Starting with the simpler unit makes this unit easier to understand.  To me the most difficult part of this chapter was setting up the problem correctly. 

E-Fields

posted Oct 11, 2010, 2:31 PM by Vanessa Cordeiro   [ updated Oct 11, 2010, 3:00 PM ]

The idea of electric fields was really hard for me to understand at first.  I did not really know when to use which formula, but after working on the practice problems it became easier.  For me the hardest part was understanding how to solve problems that asked what the electric field was based on surrounding charges.  By thinking of what a positive charge would feel in that spot, it made it easier for me to understand how to solve the problem. For example the electric field near a positive charge would be in a direction opposite the charge. 

Kinematics

posted Oct 11, 2010, 2:09 PM by Vanessa Cordeiro   [ updated Oct 11, 2010, 2:31 PM ]

The webassign part of the summer work was harder than i thought it would be, because i had forgotten much of what we had learned last year in class.  Looking up the topics in the book really helped me to refresh my memory and I think the online book would have been really helpful it if had been working, since each problem is connected to the needed chapter.  In my opinion projectile motion is the most difficult of the topics, but drawing a picture of the problem helped me understand it better.  Also doing the labs was easy because we all worked together but analyzing and writing about them was hard and took me a long time. 

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