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# JesseLefler

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1. ## Sunflower Seeds

As I'm sure many of you know eating sunflower seeds is a very popular task and one that is full of physics. Such as when you are biting down on the seed to crack it you are putting a force down onto the seed that is needed to crack but did you know that the seed is putting a force onto you. Indeed the seed is putting a force onto you called the normal force. This helps allow you split the shell. Now when you spit out the sunflower seed you are doing a kinetic equation that will affect the distance that you are able to spit the seed. Such as if you want to spit the seed farther you have to give it an initial velocity. Then this in turn will give it a larger displacement and will result in a final velocity of zero because the seed will have landed on the ground. This is the physics involved in spitting out sunflower seeds.
2. ## Iron Man

Throughout the Iron Man franchise, tony stark uses an arc reactor to stop shrapnel from piercing his heart, but how is this done. Well to begin with, when yinsen attach a magnet tostark's chest to use the laws of magnetism. By having the electromagnet facing the south side, it allowed the shrapnel to stop moving towards his heart and move still facing the magnet. Even still when stark made an upgraded arc reactor and told pepper to help him fix it into his chest. When pepper removed the magnet while trying the shrapnel continued its course. However when she put the new reactor in, it acted as an amplified magnet by completely stopping the shrapnel while still being mobile.
3. ## Surfing

This spring break I got to fly down to Florida to visit my friend Henry! Henry is a big surfer so while I'm down there I'm going to get to learn to surf along with him. With break now approaching, i figured it would be a good opportunity to look into a little bit of the physics of surfing! First there is a lot of basic application such as the fact that the force that the board exerts on the water, is exactly equal to the force the water exerts onto the board. However as a researched more I found there is more complexity to it than I had realized. One major principle that plays in buoyancy. Buoyancy is the ability to float which is due to the density of the board. Another reason that board is able to so easily glide across the water is due to the surface tension. If you've ever gone skiing or tubing, you may recall that when you fall off the water is seemingly hard. Well the reason for this, is because the molecules that make up water are attracted to each other, therefore their bonds are very strong at the surface. Finally, some of the basic forces play into surfing. Gravity is what keeps the surfer on the water and it pulls it down, just as the normal force, equal in strength pushes back up from the water. Then there is also the frictional force from the water between it and the board. However this is attempted to be kept at a minimum, which is why surfers wax their board to create a very smooth surface, decreasing the amount of friction. Obviously there is a lot of physics involved in surfing and I can't wait to give it a try next week!
4. ## Roller Coasters

When riding a roller coaster, gravity is one of the main forces. When the cart on the roller coaster travels to the top of the hill, it’s the acceleration due to gravity that brings it back to the start. When the cart gets to all the way up to the top of the hill, gravity ends up pulling it down. The cart starts at a slow pace but gets faster as it approaches the bottom. As it begins to climb to the next hill, the speed slows down. This is because the acceleration due to gravity is 9.81 m/s^2. As the roller coaster cart begins its fall from the lift, its velocity increases which causes the cart to gain kinetic energy. So therefore the faster the cart moves, the more kinetic energy it gains.
5. ## Curling

In the upcoming Olympics, curling is my favorite sport to watch. Although many people find it boring to watch I think it is very interesting to see how it all works. The stone that is being slid down the ice is very heavy so that it can slide down the length of the ice without slowing down. The velocity of the stone is only a few meters per second. Before the game begins the force of friction is lessened by spraying water on top of the ice which freeze into little pebbles of ice that help the stone move down the ice. Lastly the people who are brooming help this as well because it rids the dirt from on top
6. ## Fast & Furious

In the movie Furious 7 there was a really cool scene where they dropped their high end cars out of a military plane with parachutes with the drivers in them in hopes to land on a road and continue driving. To shoot the scene they actually did it dropping two cars out at a time with parachutists following on the way down with cameras. At 12,000 feet the skydivers had to follow the cars at the angles needed and dodged falling debris. The shooting for this movie not only took caution and creativity but a knowledge of physics as well.
7. ## Videogames Physics

If you ever played any type of fighting game you've probably witnessed at some point in time that you are mashing every button to improve your chances of winning. The action of button mashing involves quite a bit of physics. For every push down of the button physics in involved, starting with the press of the buttons for each time you push the button down the button applies the same amount of force back onto your finger. That is called the normal force. Every time the button comes back up to its original position it is most likely due to the fact that there is some kind of spring involved. Springs are commonly involved in physics when dealing with forces. Overall I hope you learned something and maybe next time you're playing a fighting game or any type of game that involves the pressing of buttons you'll remember this little reading.
8. ## Magnets

A handful of magnets are found on almost everyone's refrigerators at home. But how exactly do they work? To begin, the magnets on my fridge stick to it from both sides. When I attempt to make other metals stick to it, they simply fall. Therefore, the fridge must be magnetic attractable, meaning that it will be attracted to either side of a magnet and becomes polarized by the magnet. In addition, there are invisible magnet field lines on the magnet, flowing from north to south. The pictures of attached to the magnets between the magnet and the fridge only stay up due to the strength of the magnet. This explains why some of the magnets will not hold some of the heavier papers.
9. ## Basketball

Basketball has so much to do with physics! First off when you dribble a basketball, the force you put on the basketball, the basketball puts back on you. When you shoot a basketball its projectile motion. The ball goes is attracted to the ground because of gravity. Your shoes do not slip on the ground when you are running because of friction. When you fall and get a floor burn that is also due to friction and so painful. The amount of force you apply to the ball and the angle and location you shoot it from decides where it goes. During games ideally when you pass you want to put as much force as possible into it so its difficult for the other team to steal it. If you happen to miss your shot and the ball collides with the backboard or the rim, the momentum is conserved. That is why in warm-ups when everyone shoots at the same time its good to be aware of your surroundings because if that ball bounces right into your face it will not feel good. If you know your physics basketball can become a lot easier.
10. ## Captain America

In the recent installments in the captain America movies, we see the captain using his shield to knock out the Nazi's during Wii but how doesn't it kill them. as we have seen in the movies when he throws his shield hard, newton's third law states that the amount of force is equal to the thing it transfers its energy to. so as the captain throws hard, the shield should have enough force to decapitate the enemy. also when Peggy shoots cap's shield, it makes a large vibrating sound. this is because the lognioitutional waves in the combustion form a mechanical wave, which is moving left and right in terms of the wave pattern. thank you for listening in the physics in captain America
11. ## Soccer

I played soccer for about 3 years, and never understood that physics applies to all aspects of the sport, as it does to every sport. For example, kicking the ball into the air is an example of projectile motion. The ball is launched at a certain angle above the ground, or the horizontal, and lands back on the ground. During this entire time, the ball is being acted upon by gravity, causing the acceleration to be 9.81 m/s^2. Also, when the ball reaches it's maximum height, its velocity is 0 m/s. Lastly, Newton's 1st Law states that an object at rest stays at rest, and an object in motion stays in motion in a straight line at constant velocity, unless acted upon by a net force. This law applies to soccer, because when a ball is kicked but does not leave the ground, its velocity decreases as the time and distance increase, because it is being acted upon by friction, a net force.
12. ## Tug o War

After learning about Newton's 3rd Law, I thought about tug of war. I now know that when someone on one side of the rope is pulling on the rope, the force the person is applying to the rope and the force the rope is applying to the person are equal, no matter how hard the person is pulling. However, although the magnitude of the forces are equal, the direction of them are opposite, since the person is pulling the rope towards him/her and the rope is pulling away from the person. Also, I look can look at the net force between someone pulling on the rope with 200N and another person on the opposite end pulling with 100N. The net force of these two forces would be 100N towards the person pulling with a force of 200N. Lastly, due to the solution of the net force, this shows that the forces aren't at equilibrium because the net force isn't at zero.
13. ## Dodgeball

Last year I was involved in the Dodge for Josh Dodgeball Tournament. This tournament raised money for the Josh Rojas Foundation. This event proved how physics can not only be fun but at times can also be painful. In the game of dodgeball the entire objective is to create and form collisions. In this sport there are two typees of collisions, inealastic and elastic. One can witness the collisions by watching a player get hit by a ball or when two balls collide into one another. IN an elastic collision, the total momentum and kinetic energy are both conserved. In an inelastic collision, the two objects move as one object and one mass. In this collision the momentum is conserved meanwhile to kenetic energy is being converted into internal elastic potential energy. The remainder of the kenetic energy is then converted into heat and sound energy. This tournament went by too fast but I guess that time truely does fly by when your having fun!
14. ## Radar Guns

Some people might say that snow or rain or other forms of bad weather would be the easiest way to cause people to drive slower and safer, but in reality a police officer sitting on the side of the road is the easiest way to make everyone slow down. You will never see a more drastic change in people's driving behavior. A person could be going upwards of 80 mph but the second they realize their is a police officer, they immediately slow down usually to below the speed limit to guarantee they don't get pulled over for speeding. The radar guns police use, uses physics to help find out if the driver is going too fast. As the police officer aims the radar gun at cars passing by, the gun sends out radio waves toward the car. Then, the radio waves hit the car and bounce back toward the gun. The gun then measures the frequency of the returning waves, so the faster you are going toward the police radar gun, the higher frequency the waves will be. This concept uses a lot of physics including radio waves, frequency and also the Doppler effect. Since the car is moving toward the gun, the frequency of the returning radio waves will be much higher.
15. ## Driving

I am a horrendous driver. Perhaps reviewing the physics of driving will somehow make me a better driver. There's probably some sort of correlation between driving a car and all the other units that I've learned in physics, but the only unit I can think of right now would be the momentum and impulse unit, coincidentally one of my least favorite units. First of all, momentum is the equivalent of an object's mass times its velocity. So, if I wanted to find the momentum of my Mom's Nissan Ultima on a snowy day, I would take velocity of the car, .01 m/s, times its mass, 3000 kg, to get a momentum of 30 kg x m/s. Next, the impulse of an object is measured in several ways, including finding the change in momentum. If the momentum of my mom's car shifts to 20 kg x m/s, then that means to find the impulse of the situation, all I would have to do is subtract the two values, to get an impulse measurement of 10 Nxs
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