Force Diagrams

Hello! Wow, it's been a really long time since I last posted something on this blog, and I apologize. To make up for my absence, I have a very exciting topic to talk about today; Force Diagrams! I know what you may be thinking: What in the world is a force diagram? Well, today I will tell you all about this interesting type of diagram.

A force diagram starts out when you are given a situation to analyze. For example, the situation could be something like: A bird sitting motionless on a perch. Next, you draw a dot on your paper, and you're done! Just kidding, though I wish it was that simple... Anyways, after drawing the dot, you have to figure out what forces are acting on the object, which in this case, is the bird. Since the bird is sitting motionless, no forces are making it move either up to down or left to right. As we all know, gravity, or "Earth Force" is pulling on the bird, and the perch is reacting by pushing back up. In force diagrams, there is always a reaction to the force (kind of like action and reaction in Theater). So, know that we know which forces are acting on the bird, we have to find a way to represent them on our diagram. Below, I drew out the force diagram for this situation, and I will go through it. We represent the forces by drawing one arrow upwards (the perch which is pushing up), and one arrow downwards (the Earth pulling). To be able to know which force is acting on the object, you have to label the arrows. You first write a capital "F" like I did below, and then add the dealing and feeling force as the subscripts by putting the first letter of the name. If the two forces are congruent like they are in this situation, you add a congruent mark to both of the lines. Force diagrams aren't that hard to master, but practice is required.

My Opinion on Force Diagrams

When my class first started learning about force diagrams, I assumed that they would be easy to create when given a random situation. This may seem like a fairly simple concept to learn, but there is much more than just drawing arrows in random directions and swiping on congruent marks to it. I feel like every mark you make on a force diagram is a commitment. A commitment that says that you believe that these forces are acting on the object, pulling this way, and are very strong. It all depends on how you interpret the situation given, an with one wrong mark, the whole diagram could be demolished. That is why it is very important to choose markings on a diagram carefully and to really think about the scene. I think I understand this concept, but sometimes when I think I know the diagram for an object, it turns out that I made a mistake. There are many factors that need to be thought of while making a diagram, such if the object is moving at a constant velocity, which direction it is moving in, and many more. Overall, force diagrams seem like a very easy subject, but it should not be assumed that they really are a breeze. Never judge a book by its cover!

Acceleration

Hi, everyone. Today I am going to be talking a bit about acceleration. First of all, my class came to the conclusion that acceleration is the change in speed of an object over time. An object is accelerating if it is changing its velocity. A lot of sports announcers say that acceleration is when a person is moving fast. Acceleration actually does not have anything to do with going fast. An object could be going fast but that doesn't mean that it is accelerating. To accelerate, the object has to change its speed over time.
When an object changes its velocity by the same amount each second, that is called constant acceleration. Many times acceleration is confused with a different term or meaning.
If you want to find out more about acceleration, click on the video below.

Low-Friction Car Lab

Low- Friction Car Lab
Hello! Recently, I conducted a very fun lab in Physics class using something called a Low-Friction Car. It looks like a rectangle with tiny wheels, but is apparently extremely expensive. If you set it on a flat surface and give it a tiny push, it will be able to move far. In this lab, my group set a ramp on a higher surface. We pushed the car down the ramp, but I'm making it sound way easier than it really was... We used an app that gave us a beat (called hocks, I think) and we used a whiteboard marker to quickly mark five dots while the car was rolling down the ramp. This was a very difficult process, and our "dots" often ended up looking like dashes which didn't provide us with completely accurate data. Anyways, we found the position of where the car was at each mark. We graphed our data and found out that it was polynomial (looks like a curved line going up). Next, my teacher told us that we would be doing the same thing again, but using a motion sensor to give us accurate data. Motion sensors are my favorite! We received a packet which showed different ways we had to use the car and the ramp. Unfortunately, my group isn't finished with that packet yet, so I will save it for a different post.

This is kind of what the car looked like!

Velocity

Hi, everyone! Today I am going to be talking about velocity. So first of all, what is velocity? Velocity is speed, but with a direction. To find the average velocity an object is going, you divide displacement by time. What is displacement? Displacement is the total distance the object covered. We often look at velocity vs time graphs. These graphs show us how fast the object was going and in which direction it was going. It tells us how much time it took for the object to travel how far it did. Go to this website to see more velocity vs time graphs and to learn more about them: Velocity vs Time Link   Also, watch the video to find out more about it. Velocity vs time graphs seem hard at first, but once you understand what's going on, they're easy to understand.

Scientific Notation

Hi everyone! This is going to be a short and simple post. I just wanted to talk about a concept that some people don't know about; scientific notation.

Scientific Notation

	If the number is 10 or greater, the decimal point has to move to the left, and the power of 10 will be positive.
	If the number is smaller than 1, the decimal point has to move to the right, so the power of 10 will be negative.  Here are some examples:  10000 = 1 x 10424327 = 2.4327 x 1041000 = 1 x 1037354 = 7.354 x 103100 = 1 x 102482 = 4.82 x 10210 = 1 x 101 1 = 1001/10 = 0.1 = 1 x 10-10.32 = 3.2 x 10-1 (not usually done)1/100 = 0.01 = 1 x 10-20.053 = 5.3 x 10-21/1000 = 0.001 = 1 x 10-30.0078 = 7.8 x 10-31/10000 = 0.0001 = 1 x 10-40.00044 = 4.4 x 10-4 If you need more help, click this link. Scientific Notation

Ultrasonic Motion Detector Lab

Hello, everyone! Today I am going to be telling you about one of the most fun labs I have conducted. I was in a group with two other people, and we were given a packet which had many position v. time and velocity v. time graphs on it. One of the graphs has a line on it and the other was blank. We had to find out how a person must move to get the graph, make a motion map (check out my last post to find out about motion maps), and show what the other graph's line looked like.

Supplies:
- Motion Detector (it makes a weird beeping noise!)
- Laptop with the Program
- Explorer (A calculator like device that is plugged into the laptop to give data)

The program on our laptop gave us both the Position v. Time graph and the Velocity v. Time graph. Each of us had to align the motion detector which was set on the table with our body. Next, we walked in a line in different ways for each graph. Sometimes we had to stand still, like when the Position v. Time graph had a straight horizontal line on it. We found that when the line on the Position v. Time had a negative slope (went downwards), a person must walk from the starting position towards the motion sensor at a constant speed. When the line on the same graph had a positive slope (going upwards), a person didn't start at the origin and walked at a constant speed in one direction. When the line on the Velocity v. Time graph was a straight, horizontal line, the person had to stay in one place and not move. The corresponding Position v. Time graph was also a straight horizontal line.

What I Thought About This Lab
Like I said before, I thought this lab was really fun and interesting. I liked having to think about how a person has to walk to match the graph. It was fun to walk it out and compare my graph results with the other people in my group. This was my favorite lab that we did so far. It was easy most of the time, but sometimes the way we walked wasn't accurate and we had to try to walk again.

~If you want more information about this, click the link below~ 

More About Motion Detectors

Motion Maps!

Hi, everyone! We have been learning about something called 'motion maps' in class. First of all, lets talk about what a motion map is.

Motion Map: Represents the position, velocity, and acceleration of an object at various clock readings.

The velocity and direction the object is moving in is represented by dots and arrows. If the object is going left, you draw the arrow to the left. If it is going right, then you draw the arrow to the right. If the points on a motion map are spaced farther apart, and the arrows are longer, then you know that the object is moving faster. If there are multiple dots in a line at one time, then you know that the object has stopped moving and is resting in that position for some time.

Reflection on Motion Maps:
I personally think that motion maps are very simple and easy. I like drawing what an object was doing and figuring out how an object is moving on a motion map. I am actually very happy that we are learning about this, because it is both fun and easy.

Are you having trouble with Motion Maps? Don't stress out. This video really helps explain the concept; you'll be a master in no time!

If you want more help and an in depth explanation on motion maps, click this link. It will really help!

More About Motion Maps!

(My next blog post is going to be about something very exciting and fun.... Motion sensors!) Hope you all have a great weekend, goodbye!