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!
