collisions

This was a good weekend. Class day was fun, went to the beach, caught up on sleep, and ate a lot of food, but best of all, I got my fat boot off so i don't need my crutches. And for the record, Doc, I got my cast off on wednesday, went to class day, and I actually didn't screw up my ankle like you said i would hahaha. Anyway, this weekend my cousins from Washington came to visit and I got to hang out with my two nephews, Tyler and Tanner. They love cars and they especially like to play the ds game mario kart. They had their small collection of miniature race cars and we were pushing them around, when a two of them collided head-on and I thought, "Oh shnap! Elastic collisions and the conservation of momentum!" We were pushing them on a smooth wooden floor so there wasn't much friction but this is not quite an elastic collision because the total kinetic energy was not conserved. However, if I only include the two cars in the system, momentum is constant the collision is an action-reaction force with equal magnitude. The velocity of one is positive but the velocity of the other car is negative so the momentum and net force on the system is 0. We also played tons of mario kart and there were many two-dimensional collisions. These collisions happened super fast and they were in the game, so there is really no way to calculate the degrees and stuff. It's amazing how physics just pops up everyday!

Momentum in sports

I didn't get to do much this weekend because of my sprained ankle. I was bummed cause I couldn't go play a for fun game of softball with my cousins. BUT after learning about momentum, I noticed that it is evident in many sports including baseball and softball, volleyball, and tennis. In baseball, a batter like Prince Fielder with more mass can hit the ball farther because what determines how much force is applied to the baseball is the impulse during the split second that the baseball is hit. Impulse is the same as the change in momentum, and the momentum is mass times velocity so the more mass the batter has and the faster the players swings the bat, the farther the baseball will travel after contact. Also, in volleyball, hitters, if possible, take the farthest approach so that they can have more space to run and gain momentum before hitting the ball. The faster the velocity of the player, the more momentum, and thus, the player can hit the ball harder and with more force.

sprained ankles suck!...BUT i made doc laugh!

TWO sprained ankles in half a year. Ridiculous! Anyway, last thursday, I was at volleyball practice and we were practicing our triple blocking. I was blocking on the right side, so i had to go all the way to the left to block the left side. Ok, so our team isn't really that good at blocking so everyone was kinda drifting and it was pretty much all over the place. BUT i was the only one unlucky enough to land on someone else's foot, rolling my left ankle on the way down. My left ankle swelled up to the size of tennis ball, which was exactly what happened to my right foot just a couple months ago, so I guess one good thing is that both my ankles are now even in that both are messed up. But anyway, what I wanted to get to was that I finally made doc laugh! (even though I totally did not think it was funny). I dont think many people can say that they made doc laugh so I'm quite proud. This happened on Friday as I had to print out my paper and I now walk really slow so I was still getting my stuff together when period three already started. I was putting all my stuff into my bag in front of doc's period three class and all of a sudden, he just starts cracking up and i realized that he was laughing at me. I don't know what it was but I guess me being a cripple was pretty entertaining to him. Hahah so yeah thats my whole story about me making doc laugh.

Anyway, while I was all frustrated lying down, icing my tennis ball-sized ankle, I was watching my teammates scrimmage another team on Thursday, and I suddenly noticed how much physics occurs in volleyball. When the volleyball is put into play, gravity constantly affects the motion of the ball. Even when a player serves the ball, and goes into the air, gravity acts upon it at a constant acceleration. Air resistance is also in effect although there is an incredibly tiny amount because we were indoors. However, in beach volleyball, the wind and air resistance is a big factor as the path of the ball becomes increasingly hard to predict. Also, when a player sets the volleyball, it is a form of projectile motion as the player's hands apply a force to the ball and makes it travel to its destination. Forces are in effect the whole time as the players apply force to the volleyball when they spike it. Even in between points, when the players are just standing on the court, gravity is pushing down on them and a normal force going directly upwards is present. The grip between the volleyball players' shoes and the ground also causes friction so that they don't slip on the wooden gym floor. Finally, when a player goes up to spike the volleyball, they take a running start or an approach. This is a period of kinetic energy, but when the player jumps to hit the ball, this is transferred into potential energy as he or she goes up into the air. The higher a player jumps, the more potential energy the player has. So from spraining my ankle, I realized how much physics is involved with the sport of volleyball.

physics in tennis!

While playing tennis last weekend, I noticed that a great deal of physics is involved in the sport. It was quite windy on that particular day, so the motion of the tennis ball was constantly affected by air resistance, which we learned how to calculate in class. Personally, I don't like playing in the wind because it is a lot harder to control the ball and to hit the ball cleanly. Anyway, I also found that friction acts on the ball when it hits the ground, especially when there is a lot of backspin on the ball, causing it to stay lower on the ground. This leaves the ball on the ground for a longer amount of time as opposed to topspin, so there is more friction occurring when the ball has backspin. Also, constant forces are being applied when the racket hits the ball, and then the ball is at all times influenced by the force of gravity. Forces are not only acting on the tennis ball as the players are also influenced by outside forces. This would include weight, a force directing straight downwards, as well as a normal force, perpendicular to the ground directed upwards. Even friction is present when the players run as their shoes come in contact with the ground. Physics is everywhere!