Some notes

More mass, harder to accelerate, longer period
Amplitude/drop height no effect
Spring constant t= c1/square root k
Is the y intercept neglible for mass
2 high r squared values suggesting linear and power
Power fit was agreed on
T=c square root of mass

T =2pi square root of m over k
Simple harmonic motion

Mass affects spring oscillation

Pendulum not affected by mass
2pi square root of l over get

This is all a little confusing to me, especially since I'm a little unfamiliar with simple harmonic motion. I'm also really bad at the graphs that were on the first page of the quiz, I need to learn how to do that.

Centripetal force

The centripetal force is directed on an object in a circular motion towards the center of the circle. We were given a helpful packet with equations and explanations. On the quiz, I did pretty well. I got all the momentum questions right and on the centripetal part, for acceleration I did 4pi^2/t which it should've been t^2. I guess what sort of confuses me is where the force comes from. Like if you think of a runner on the track, the friction is the centripetal force. Its a little confusing that the friction causes the runner to go inwards, but if you think about it, the runners natural tendency would be to go straight. If you look at the diagram above, the runner would follow the path of inertia, but due to friction it doesnt. But this is still confusing I'll be honest. In the picture above is the force coming from the string or the person?
Im decent with calculations and what not because the equations are given. So if the question is asking for velocity, you plug the known information in one of the given equations, but its understanding the equations, and breaking them apart to figure out where they're derived from is what is difficult for me. I feel like I have a general understanding of centripetal force, but I need to work towards a deeper one.

The flying pig, here is a picture of our work. We were trying to find the force on the string and this involved many different equations such as the pythagoreum theorum and the force equations. We had to find the force on the string, so as you see we drew a force diagram. We decided to find the earth force (mass) and the centripetal force, and then with our vector knowledge, we could use the pythagoreum theorum to find the hypotneuse aka the force on the string.

Reflecting on Reflecting!!!/Momentum test corrections

YIKES! My last blog was in January. I feel like since february is a short month, and we've had a break in between, I've been thrown off my blog schedule. Excuses, excuses. Honestly, I think the reason I haven't been blogging is because I put off blogs when I don't understand something. I know this defeats the purpose of reflecting, because if I don't completely understand something I could easily say "this is hard for me to grasp because..." but for some reason I just put it off. I guess I just like to know what I'm talking about, and also sometimes I just don't know what to say in a blog if i'm not understanding the class material. Basically, my last blog was on energy...so that means I skipped over momentum.

Momentum
Momentum was interesting because I though I understood it...and then the test came and :((((. Honestly, I seriously understood all the problems we've white boarded in class so when I didnt do too hot on the test I was slightly surprised because i understand P=MV. Okay so on that test, I didnt even really attempt the last question because the graph confused me, but now I totally get it and i'm like REALLY.
So the graph is a FORCE vs Time graph, and I didnt process that FORCE MULTIPLIED BY CHANGE IN TIME IS IMPULSE. honestly like duh.
So now the problem is straight forward.
A. Impulse of the rocket engine?
F=20 T=.5
(20)(.5)=10
Need to account for the triangle
10(.5)
Answer: 5kgm/s

B. determine rockets burnout velocity
5=.3v
divide by .3
vf=16.7 m/s

C. Determine acceleration
a=v/t
16.7/.5
a=33.3 m/s/s


ON NUMBER 17 I CONVERTED WRONG. honestly the dumbest reason to lose points for. I ALWASY CONVERT CM TO KM. I think its a habit of mine just to turn everything into kilo, but centimeters goes to meters. I literally messed this up on the centripetal quiz the other day too, same exact mistake.

19. I didn't account for direction, and this is important with momentum. Other than that my work is correct

Ratios are too much to reflect on the blog here because I got basically all those wrong. But I went over these with my table and I am aware of what I did right and what was wrong, and I have notes and everything on that. Overall on this test, the ratios were the only thing I feel like I was weak on, but I think since then my understanding has improved.

LOL charts

Another fairly simple topic is LOL charts. We are very familiar with these because we did these freshman year and then in chem again last year. So I didn't really struggle with these. Basically you identify what's in the system. Then you identify what energies are present at that moment of time. For instance, in number one in position the cart is not moving. It has elastic energy from the spring, and then in position b the cart is both in the air and moving. This means it has both elastic and kinetic energy. Basically how I think of it. Is moving?? If yes then it has kinetic. Is it off the ground??? If yes, then it has gravitational. Is there a spring involved in that moment??? If yes, then it has elastic. #2 on the paper is a little tricky. The idea of Work is introduced. The problem looks identical, except it says to exclude the spring from the system. Since there is no spring in the system, you can't account for the elastic. So how did you get from point a to point b?? The energy had to come from someone. You call this work. And as you see, the last problem involves dissipated because you need to account for friction. Note on those charts, dissipated is not on the first LOL chart at position A but only the one at position b. The energy could only go towards the friction if it is moving, therefore it would not make sense to have dissipated on the beginning. Overall this was just a big review from freshman year, so I found this fairly easy.

Energy pie charts

The question is on the paper, the answers are on the white board. These problems were fairly easy. I didn't struggle much with them. The one thing that was introduced to me was dissipated energy. Before this, I feel like we would neglect friction and air resistance, so often times I forget to include that. Dissipated energy is a new concept, that I didn't know about before. It's basically when the energy into the system goes into something else such as noise, friction, air etc. For these pie charts, they are good representations to see what energies are increasing and what energies are decreasing. For instance in number five, as the you is going higher, there is more gravitational taking away from the elastic while the kinetic remains the same. I think these were easy, and a nice way to introduce a new unit

Test Corrections

^ represents the delta change sign because I don't know how to get a triangle

I don't have a blog of the kinematic equations or one about parabolic motions mainly because of confusion. At the time of learning, it's difficult to reflect and do a quality blog when I was confused because I had no idea what to write. But now that we have had a test, it's easier for me to reflect on this because there is something physical there, where I can explain what I did wrong and what I didn't understand.
So for number 15
The problem is
A diver running 3.6 m/s dives out horizontally from the edge of a vertical cliff and reaches the water below 2.5 s later
How high was the cliff?
What I did?
I tried using the a=^V/^t
And then I plugged in ^v in the 1/2a(^T)^2 +vi^T equation
which doesn't really make sense because initial velocity is definitely not the same thing as change in velocity. It is fair to assume that the initial velocity is 0, so you just plug the info you have into the change in position equation, and you would get out around 31 meters for your answer. 
How far from the base of the cliff did the diver hit the water? 
I can't even understand my work here and I don't know why I got it wrong. I feel like a lot of times with these problems I try to complicate it, and I think it possibly can't be that simple when it is. Basically, If you go 3.6 m/s and there are 2.5 seconds, you just multiply 3.6 by 2.5 and your answer is 9 meters.
17
A soccer ball is kicked from the ground and lands on the ground 2.2 seconds later
What is the initial vertical component of the ball's velocity
Once again I don't understand my work. But I overcomplicated it again,
Basically if you are trying to find the initial velocity, you can assume the position is 0, and then solve from there. You plug it into the the 1/2at^2 equation and your answer is around 11m/s
How high does the ball get above the ground
I didn't even answer this question, but since my vertical velocity was wrong this would be wrong too. Basically now you would plug in the vertical velocity in the equation and get out the change in position. But, you would need to use 1.1 seconds instead of 2.2, because 2.2 would give you the end results...since it is a parabola the maximum height would be at half the time.
If the ball was kicked at an angle of 55 degrees above horizontal, what was the balls total initial speed?
Once again, I got this wrong because I had the wrong vertical velocity. I did do the right process with the wrong velocity, but that doesn't matter. If i did the same thing, except using 11m/s, I would get the answer 13.4.
Basically, on a lot of problems, I mess up the process on one thing and then the rest of the problem is completely wrong. So i need to take my time and think what I am doing wrong.

Friction

We've started the topic friction, which was negligible up until now. I think friction has always been something we've known about, but never really understood. In class, we did a lab where we tested what objects and materials are affected by friction. We had tested how shape, speed, surface area, and material effect are affected by friction.
Results
Shape- No Relationship
Speed- No relation
Surface Area- No Relation
Material- Yes
Force- Yes

The one that blew my mind here was the results of shape. I feel like personally, in my mind a ball would roll down a hill much faster than a box would. But typically, in a real life scenario, a ball and a box do not have the same material. In this lab we used the same material, same amount of force, and saw the amount of force applied remained the same. I feel like when I think about it now, the same material will create the same amount of tension with whatever object, so shape does not really matter. I think the rest of the results were fairly predictable. My group decided to do the force lab differently than other groups by changing the angle at which the object was dropped from where as others used a force o meter.
We were introduced to an equation

We were given a packet, and those problems were fairly simple to do. The idea of static and kinetic friction came up which was something I've first hear about, It the idea that to get an object going it requires force but it might not move, but when it does move you apply the same kinetic force.
Overall, I like the friction problems and I find them fairly easy to do.