Force Diagrams

I just realized that the last post I published was in December... Sorry for not posting in forever, however I highly doubt that people are actually reading this. Anyways, during these 2-3 weeks, we learned a new topic in Physics class: how to construct and analyze force diagrams.

To begin with, a force diagram helps you select relevant forces and represent them with vector notations. There are 4 different types of forces, gravitational, normal, tension, and frictional. *Just a remind that we aren't allowed to use the word, "gravity" in class, so we use, "earth"  instead.


Here is our scenario. This was the very first one we went over in class together.

The dot drawn on the paper represents the bird, or the object. Now, let's talk about the two subscripts that are indicated there. The small P is the "dealer," or the object that exerts the force, while the small B is known as the "feeler" of the force, or the object that experiences the force. The big F just stands for force in general. Moving on to the actual representation of the letters, the P stands for the perch and the B stands for the bird. As you can see above, the arrow is pointed up, indicating that the perch is holding the bird up and the arrow pointed downwards, represents that the earth (gravity) is pulling the bird down. The last thing I want to mention are about the two small dashes on the lines. They tell us that the lines are equal, or balanced forces. The bird is motionless and not moving, so they are equal. If they were unequal, or unbalanced forces, then one would have more force than the other, in which the lines would be not equal in length.

Reflections: The scenario given above was fairly simple in my opinion, however the more complex ones, are very confusing. After I finished drawing my diagram, I looked to see what other people had and they had something completely different than what I did. This topic is a lot harder than I thought and I don't like it that much because it frustrates me. Going to a totally different topic, I hope that we can quickly switch groups because I feel that I'm always isolated and along with that, they go too fast. I do try speaking at times, however it seems to me that they don't even consider what I say or even look at me, while talking. I guess I'll just ask my other friends to help me understand this concept. Finally, I do realize I don't talk at all during white board discussions. I'm just so scared to speak up because I feel that my questions are stupid and maybe, repetitive. I may seem comfortable at times, but really, I'm not to be honest.

I will upload another post on other complex scenarios of force diagrams, however you may have to wait a bit becuase I still haven't grasped the full concept very well. Wish me luck guys and I hoped this helped in a way!

Low Car Friction Lab

Hey guys, so yesterday we did a low friction car lab in physics. That was pretty amusing... You'll get what I mean later. First, we laid a 2m ramp (high-low) across our desk. Along with that, we used a metronome and for those who don't know what that is, it is an electrical instrument that makes repeated clicking sounds at an adjustable pace (musicians use these). We set the pace at 120 hocks. Then we took our low friction car and located it at the high end of the ramp. There as it slid down, Alex (one of the lab group members) marked on the ramp, for every hock that ticked. We needed at least 5 data points.

 

 

Low friction car

Data



When we first began this experiement, we screwed up, so that was pretty hectic (that's why I mentioned it was amusing). We didn't measure the position of the car, but instead, the distance between two points. Anways moving on, as you can tell, the prediction my group came up with was correct. During the white board discussion, there was one group that had problems with their graph. We said that they could've pushed the car slightly, or their calculations might have been off (human errors). Continuing on, our class came to the consensus that the velocity vs. time graph would be a diagonal line because the car gets faster as it goes down, which results in the slopes changing. The velocity vs. time graph could not be a straight, horizontal line because it was not going at a constant speed. Lastly, we concluded that this graph was a polynomial graph because it had a curve, as it was going up.

Reflections: This experiement was alright. I thought the class discussion was very boring and confusing towards the end. Mr. Battaglia was writing things on the board and I wasn't very sure. I didn't ask questions during the discussion, which I should've. My mistake.

That's about it guys, thanks for reading!

Velocity vs. Time Graphs & Displacement WS 4

Guys, I'm back! How's your thanksgiving break so far? My schedule has been packed, but I'm having tons of fun though. I'm a little disappointed that breaks almost over. :( It's so unfair! I wish it was two weeks long. That would've been awesome! Well anyways, let's get back to physics! My class had a white board discussion last week on Friday. We did not go over the whole packet because there wasn't enough time. I might have not covered all the information here because I wasn't in class for the first 30 minutes. Anyways, the two sheets we analyzed as a class are provided below.

Part 1

 

Part 2

 

Part 1.) One of the things my class came to the consensus was that the reference point could be any point on a graph. It does not always have to be at the origin, or the starting point. We also agreed that the cross hatched area on the graph from question 1c represented the total distance traveled by the object. Part 2.) We didn't talk about this one much. We all came to the agreement that for 2d and 2e, all you have to do is count the boxes within the given time. For 2f and 2g, my friend helped me step-by-step on how to determine the average velocity and speed. By the way, we did not go over these ones in class. 2f.) (Formula= final position- initial position over time elapsed) First, figure out the final position the object was at 8 seconds. Then find the initial position at 4 seconds. Take the final position and subtract that by the initial position. (5-7= -2) Lastly, divide that number with the time elapsed, which was 4 seconds. (8-4=4) The final answer you should get is -1/2 m/s. 2g.) (Formula= distance over time) First find the slopes between 4-5 seconds, 5-7 seconds, and 7-8 seconds. In order to find the slope, you must do rise over run. The slope of the first time is 3, the second one is 0, since the object was not moving, and the slope of 7-8 seconds is -5. You must add 3 and 5. Remember, distance can never be negative, so you don't subtract. After you add those two, you divide them by 4. (8-4=4) Your final answer should conclude to 2 m/s.

 

Reflections: Our class discussion was pretty horrible... There were people arguing and debating whether or not the answer was right. We were literary on the same topic for almost an hour. Not joking. As you can tell, we didn't get that far. Furthermore, the discussion was pretty confusing. When someone asked a question, it was answered unclearly and they just rambled on. My teacher was also pretty upset and yelled at us. 

 

Unit 2 Worksheet

Hey guys! We just recently did a worksheet in class this week and I wanted to share it with you all. I really don't have much to say because the answers are provided on the worksheet. Ask me any questions if you don't understand it!

 

Part 1

 

 

 

Part 2

Recoverd!

As you guys can see, I got all of my posts recovered! They'll be up and going, so no worries guys! :) I'm just really happy I got these back, thanks to a stranger who helped me!

Re-upload: Our so called, "fiesta"

Hey guys! Apparently this my third post... To be honest, I'm not sure what we did in Physics class over this past week... I remember like a thing or two, but that's it. The only thing that sticks out to me right now (I'm extremely tired) is that we took an assessment, or our so called, "fiesta". I didn't score very well, but I mean, at least we get multiple chances to re-take the test, so we can raise our grade up. I guess I'll be okay, I think... At the end of the day though, it really depends on how much effort you put into your work and whether or not you understand the concept.

 

 Our "fiesta"





It may look like I did good on it, since there's not many marks, but if you look on the top left-hand corner, my teacher graded us from 1-3. 3 being the highest and 1 being the lowest. Well technically 0 is, but I mean that's if you literally didn't put anything down on your paper. 5,6,7,8 and 9 are the standards or concepts we needed to know for our "fiesta".

Standards/Concepts

I did well on identifying the dependent (y) and independent (x) variables and graphing the data. I would've gotten the mathematical model right if only I used different variables. I totally forgot that the teacher said we couldn't use the x and y variables. Oops! Well either way I also forgot that we had to label which varibale stood for which. I screwed up on the last question, well not completely I guess. The coefficient is wrong, the y-intercept wasn't labeled at all, and my "for every" statement is incorrect also. I did get what type of relation the graph was and whether it increased or decreased correct. I think I'll do better on my next "fiesta" if I prepare a bit more and if I get more time in class to complete it. Yeah... We took this towards the end of the class period, so I started rushing on it. It was so nerve racking.

Re-upload: Direct, Indirect, Proportional & Inverse

Hey guys, this is my second post! I hope you enjoy reading it! During my physics class, we discussed about direct, indirect and proportional relations. A direct relation is when x increases, then y also increases or if one decreases, then the other also decreases. The numbers do not have to be constant, meaning if x increases by 2, then y can increase by 3. They don't have to increase or decrease by the same number. We also said that the line on the graph would be linear and consistent. It does not always have to pass the origin.

Direct

 

The meaning of indirect obviously means not direct. For an indirect relation, we came up with, as x increases, then y would decrease or vice versa. The numbers also do not have to be constant. The line would be a negative slope.

 

Indirect

Proportional would be a constant relationship between x and y. When x doubles or triples, then y would also double or triple. The line on the graph would be linear and consistent. It must always pass through the origin.

Proportional

 

We haven't got to inverse yet, but I did make a prediction to what it is. I believe it's when x is doubled, then y is halved.

Inverse

 

My thoughts: Our class discussion actually helped me a ton and my teacher was able to help us with bits and pieces. I also participated a lot more than I expected and asked some questions. To be honest, I'm not really a risk taker. I find it very hard because I'm afraid that I won't get the answer right and people will laugh at me. I'm just really happy and proud of myself for stepping out of my comfort zone and being able to be involved in the class discussion.