Week 5: Lovebirds and a peace sign

I literally just remembered five minutes ago that I had to make/write a new post for my Physics blog. Whew. I wouldn't want to miss a quiz grade (Hi Mr. Heyler!).

Lovebirds on the left, peace sign on the right.



Approximately one and a half seconds after I remembered, "Oh, french the llama, I'm supposed to do update my Phys blog!" my head automatically snapped to the calendar on my bulletin board (I guess I wanted to check that, yes, it was still Saturday and, yes, I still had time to do it). About half a second later, my eyes darted from the box marked "Saturday, September 25th" to the two hanging...things (What do you call these? Leis? Necklaces?)...on my board.

It took almost two seconds to see Physics in my daily life. And this is only the fifth week of school.

Uhhh...WOW. I will definitely notify you when I start thinking about Physics concepts nonstop.



Anyway, on to the jelly bean of the week! This week's flavor was: FORCE. Mmmm, yum.

Newton's First Law states that an object at rest stays at rest unless a force acts upon the object, thus causing it to accelerate. The net force of the...let's call it the "lovebirds" (It's too big to be a pendant!)...anyway, the net force of the lovebirds is zero because it is not moving. The same goes for the "peace sign."

For each "necklace" (Or is it more of a lei? No word exists to describe these things!) the force in the downward direction (mg) is equal to the tension of the string's upward force (T). Please see equation to the right.

Now, if I were to pull hard, vertically, on the strings, the downward forces (mg) increase and they become greater than the tensions of the strings (T). Net force would then be negative and in the downward direction. As a result, the lovebirds and peace sign fall towards the ground. But I wouldn't want to do that, of course. I'd have to pick them up (and who wants that, right?).

And, voila, the physics of lovebirds and a peace sign.

 

Hope everyone had a great time at Peace Week at 'Iolani this week! :)

Week 3: Throwing rocks and trying to kill seahorses.

LIES. Seahorses are my friends. But more on that later on in this post.

The jelly beans for the past two weeks have all tasted the same--very projectile motion-ish. It tasted a bit weird at first, but I got used to it.

I actually planned on writing about tennis for this post. But I ended up sleeping in on Sunday morning and my brother and my dad left to play tennis way before I woke up. But that's all right, because I'm making up for it with, not one but, TWO examples to illustrate projectile motion.

So onward!

For my brother's 14th birthday this past summer, we planned on going swimming at Hale Koa. But we spent a little bit too much time playing games at Dave and Buster's after lunch. Shayne (my older sister), Josh (my younger brother, a.k.a. the birthday celebrant of the day), my cousin Josh (yes, his name is Josh, too) and I got carried away with the games so much that by the time that we got to Hale Koa, it was already a bit chilly and we didn't really care much for freezing in the pool. We were supposed to meet our parents at Koko Cafe later on for dinner, so we needed to kill time. We ended up going for a walk along the beach until we reached the Rainbow Tower by the Hilton Lagoon. While my sister and I watched, brother-Josh and cousin-Josh began to "skip stones." But they weren't really skipping stones, just trying to out-throw each other with the rocks.

I don't think you can see the rocks. But you can see, by their stances and positions of their hands, 
that they were trying to throw the rocks super hard.

At one point, they almost hit a little kid playing in the water (not shown). This is an example of epic failure. This is also an example of projectile motion.

A projectile travels in a path shaped like a parabola. In this case, the rocks are the projectiles because their horizontal velocity stays constant while their vertical velocity accelerates due to gravity.

A mini soccer ball being tossed up in the air to hit the cute seahorses painted on the wall is also a projectile.

The ball is 1.395m above the ground and the seahorses are 2.425m above the ground. My brother is standing 0.805m from the wall. I bet I can find the velocity of the ball!

So the seahorses were being repeatedly hit by a mini soccer balls moving at 4.82 m/s.
I think. I'm pretty sure. Either way, poor little seahorsies.

And, voila, the Physics of "skipping stones" and killing seahorses.