There once was a man named Newton (Unit 3)

And so we've arrived at midterms, and the end of another unit. This unit, packed full of formulas was kind of a headache, but hopefully I can sum it up in less than a few thousand words.

It all started with Newton's 3rd Law, which says that for every action there is an equal and opposite reaction. If you want to check out the examples we used to explain this law check out the video below (it's pretty awesome if you ask me)




SO MANY ARROWS!!!!! What is this madness that requires precision in arrow drawing? It isn't archery, nope, this time it's vectors. 

Vectors are kinda hard to explain so we'll start with a visual example (because everyone loves visual examples.

Now that is one spiffy image. But what does it mean? Well a vector is a quantity having direction as well as magnitude, (that's the line with the arrow!) We used vectors to determine what direction a boat will travel in a lake and what the force of tension would be on two ropes when holding an object. In this picture the force on the y axis is one direction and x-axis represents another force and direction. the line (x,y) is the vector representing the direction those forces travel when combined!

Next we hopped all the way to the sun! Well, not really, but we learned about gravity and the UNIVERSAL GRAVITATIONAL FORCE!

Here it is, right here. Look down.

We used this equation to calculate the gravity between the earth and the sun and the earth and the moon. The latter led us into this nifty section about tides! The moon is relatively close to the earth (duh!) and it travels in an elliptical (or oval) path around the earth. The force between the two sides of the Earth and the moon will be different depending on time of day and the placement of the moon. This is essentially what causes tides, the difference in gravitational force exerted by the moon on the ocean.

Next we hopped into ever MORE formulas:
Momentum=(mass)(velocity). 
Momentum=p. 
change in p= pfinal-pinitial. 
Impulse=J. J=F(change in t).
J=change in P. 

UNIT QUESTION: How do airbags keep us safe? 
Well  momentum will be the same no matter what, so the impulse will be the same. Airbags increase the time impulse occurs, which means the force will be less (remember the big F and little t?). And a smaller force will lead to less of an injury!

AND THEN IT GOT EVEN MORE COMPLICATED!?!?!?!

Conservation of Momentum. 

We learned that Ptotal before = Ptotal after. (remember, of course, that p is momentum)               

(Ma)(Va)+(Mb)(Vb)=(Ma+Mb)Vab (when the two objects collide and stick together)

 (Ma)(Va)+(Mb)(Vb)= (Ma)(Va)+(Mb)(Vb) (when they do not stick together)

            before                          after

All in all, I enjoyed this lesson. I loved its real world applications and I really learned how to "speak the language". I had been having trouble putting the things I learned in Physics class into words, and especially proper test answers and this lesson helped me learn how to do that.  All the formulas could have been overwhelming, but instead I learned how to use them and it worked out just fine!

For the next unit I want to take better notes so that when I have to write test answers and reflections I know where to find the information. I also want to work on getting these blog posts in on time (sorry, again, Mrs. L). I'm kinda looking forward to this MidTerm as a chance to prove to myself that I CAN learn sciences!