We then went over two topics - one connected to yesterday's video that mentioned the dot product between two vectors, and the other related to graphing. The dot product that we saw yesterday provides a way to calculate the component of the force in the direction of motion when we calculate work, and today we saw the equation we should use - W = F x cos(theta) x d, where F is force, d is the distance over which the force acts, and theta is the angle between the applied force and the direction of motion. Here's the equation clipped from the online notes:
We worked through an example of this and then we discussed the idea of graphing force versus distance and how the area under that curve becomes the work done, shown below:
Next we began learning about energy and the different forms it can take, and most importantly, the definition - the ability or capacity to do work. It has the same units as work (the joule), and is directly related to it. Energy is conserved, meaning it does not get created or destroyed, and only gets exchanged between objects, systems, or forms. The total is always the same. Kinetic energy (the energy of motion) and potential energy (stored energy) are the two types that make up mechanical energy, and their sum (KE + PE) equal the total mechanical energy of an object or system.We did a few examples of calculating KE, and then finished up with a review of the weekend blog assignment, which is to read the existing posts on our "Home Base" blog, and the model post you are now reading, and leave a "thoughtful" comment on one of them. Monday we will start writing scribe posts for real.
19 comments:
Nice Summary of the day. It helps to see it again.
This is really helpful, and the pictures help explain the equation a lot clearer.
Yeah I really agree with katie, this looks really helpful.
I understand that we can change the equations for example the power equation. But I’m still a little confused on how it was changed. Could you explain number 6 (again) from the homework that was due yesterday? I also have another question. We had talked about this a few days ago, but how are we supposed to tell the “W’s” apart. For example how to tell the difference between work and watts? Thanks! (Sorry I posted this in the wrong place before)
I agree with everyone's comments above. seeing the pictures and the equations definately helped me grasp the concept a lot better. but i would like to see some KE and PE problems written out so i can learn how to do it since i wasn't there friday when you guys did it.
Mr Wirth,
Nice job with the blog idea so far
Thanks all for helping to give this a good start.
Adriana - See my comment in Deniz's post.
The summary of the notes and the pictures really helped me understand the material.
I think this blog is a good idea. It's nice having the notes right on the computer to help with the homework or help before a quiz. Thanks for setting it up, Mr. Wirth
Mr. Wirth,
Sick blog. I like the pictures and whatnot, they help me get my head around everything.
This post helped me understand more of what is going on in class. Through peers I got a better understanding of the "energy and power" unit.
The pictures helped me to better understand the equations. Also, the videos on work and power in class helped alot.
Good job with the blogging sir
looking back on this post made me remember the material. it was really useful as i was doing the wkst assigned and it was a good refresher. good idea and keep it up
The overview is really helpful. The pictures helped me to understand the equations more clearly. Good first summary.
good summary
good job with the blog idea
Its good to get a review of the notes online instead of in powerpoint form
That test was so hard! I think that it should be curved because it was really difficuly. I hope the midterm is better tho...
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