IVIR

Capitals 2016

Last fall, some friends and I got obsessed with playing darts (Nate and ZZ). Although we were all relatively the same in terms of level, we each had distinct styles. I preferred to throw the dart with a lower velocity and angle the toss so it would land where I wanted it to. Nate on the other hand would throw the darts with a much higher velocity, but shoot the dart relatively straight at his target. Zach, well, he just threw the dart at the board and hoped it would stick. Anyway, although Nate's method of a straighter shot with more velocity seems appealing as the time the dart is in the air is reduced so the change in y displacement due to gravity would be decreased and also the dart would travel straighter and not wobble at all, there are some flaws to this apparent advantage. When attempting to throw the object with a larger velocity, Nate would have to increase the force of his throw, causing a larger arm motion when throwing the dart. The more motion involved in his toss allowed for more error in both the y and x direction. While my intended error was decreased as throwing the dart with a lower force allowed for more focus on accuracy, I had to judge the trajectory of the dart in my head to get it to land where I wanted. By focusing on accuracy and not caring as much about the y displacement, I was able to hit quite a few 20 pointers since the 20 point strip goes vertical from the middle bulls-eye. However, on a few rare occasions I provided too small of a force to the dart, causing the dart to bounce off of the board as it didn't have enough force to stick. In all reality, Nate and I threw it somewhat randomly like Zach, but it is interesting to think about the ideal angle to launch a dart in order to maximize accuracy to prevent the dart from straying off to either side, but also throw it with a relatively low launch angle in order to minimize y displacement. I wonder if professional players ever think about the trajectory of the dart or if they just have learned through practice.

As the upcoming CYO basketball season is nearly upon us, I have been pondering the physics behind the three point shot in basketball. Perhaps not the most proficient three point shooter (I'm more of a drive in the paint player), I am trying to expand my game to become a threat from all parts of the floor. First of all, one of the simplest concepts in basketball is that the closer you are to the basket, the higher the launch angle you have to use, so when shooting three pointers, this launch angle is roughly 45-55 degrees. Since the basket is 10 feet high, being taller decreases the launch angle necessary and velocity needed because the y displacement necessary is decreased while the x displacement is the same. Although one may expect a very large difference in the angle of a three point shot between a 7 footer and a kid 5'6", in reality the difference of the optimal angle of release is less than 10 degrees between the two. Another factor of shooting 3 pointers is that the higher the launch angle, the "bigger" the target of the hoop appears. This is due to the fact fact that a lower angle with the same total velocity has a greater x plane velocity, so when the ball reaches the height of the hoop on the way down, the greater x plane velocity causes it to have a larger chance of hitting the back of the rim, front of the rim, or missing the rim completely. When the ball is thrown with a higher launch angle with the same velocity, the x component of the velocity is decreased, so when the ball reaches the rim height on the way down, the minimal x plane velocity allows for a higher probability of the ball not hitting any rim and causing a "swish", or for the ball to gently hit the back of the rim and still land in the basket. Although this makes it seem that a higher launch angle would increase the accuracy of three point shots and make them easier, there are a few other factors to consider. First of all, it is harder to aim a shot with more arc than a shot with less arc because more arc would cause a greater time in the air, causing a greater displacement left or right due to any errors when releasing the ball. Another problem with shots with a larger launch angle is that due to the higher maximum height reached and greater initial vertical component of the velocity, the shot reaches the basket with a higher vertical velocity due to the acceleration due to gravity, causing the shot to bounce harder off of the rim instead of landing softly on the rim. Shots with a smaller launch angle will land softer on the rim, increasing the probability of an errant shot to roll in. Another aspect of three point shooting is the involvement of the legs. In the NBA and college, players can shoot jump shots well where they release the ball at the apex of their jump, which makes their apparent height larger, creating the need for less of a launch angle. Since they release the ball as their body's vertical velocity reaches 0, the velocity of the ball mimics the velocity of shooting on flat ground without bending your knees as the legs are not helping to provide any additional velocity. In CYO, generally speaking, kids are not as prolific shooters with as much arm strength, so kids bend their knees and release the ball on the way up during their jump. This helps provide some of the velocity from the leg motion, causing a need for less force from the arms to create the initial velocity, therefore decreasing the probability of error since the shooting can focus more on accuracy with their arms than power. Hopefully, realizing the physics behind the elusive three point shot will help me take my game to the next level. But in reality, I'll still probably throw the ball up and hope that eventually it will land in the hoop.

Fast and Furious, in my opinion, is one of the greatest film series of all time. This weekend, I decided to re-watch the 6th movie for probably the 4th time. Although the movie is highly entertaining, a lot of the stunts in the movie are clearly not possible in real life due to some basic physics concepts. For example, one of the biggest scenes in the movie is when Dom jumps from his car (moving at over 60 mph) and dives across the air to catch Letty in midair, and then the two of them land on a parked car's windshield on the other side of the road, yet the windshield does not shatter. On the bright side, the high momentum of Dom's leap from a high speed car does change the direction of Letty's fall in midair as they keep going in the direction Dom was originally going together, which makes sense in the physics world. The part that doesn't make sense (besides the perfect timing and impossible nature of the stunt) is that the windshield doesn't break, even though Dom was traveling at over 60 mph when he "hit" Letty in midair and then both of them landed on the windshield. The windshield should have definitely shattered from such a large impact force over a short period of time, especially since their momentum was completely perpendicular to the plane of the windshield. (See Scene 1 Below) Also, from an impact that large, both Letty and Dom would have sustained injuries, and probably a concussion (read Zach's post for more information). In the same scene, Owen Shaw is driving a tank down the highway at speeds of over 60 mph (he is able to go a lot faster than normal highway traffic), but the fastest tank in real life cannot travel speeds over 60 mph. The physics behind this is that the treads on the tank would start to have too much friction with the ground, and not spin as fast as the motor is trying to spin them. Especially with such a heavy tank, the frictional force would be extremely large, causing the frictional force to overcome the motor's attempt to spin the tread. This would strip the tread off of the motor track, and essentially break the tank. Clearly, this wasn't the most realistic scene, not to mention the fact that the mustang colliding with the bridge supports caused the tank to flip over. Link to scene below Fast & Furious 6 (Dom saves Letty).mp4

All my life I have skied and snowboarded in the winter, frequently hanging around the terrain parks at Bristol. Early on I would watch in awe as people went off the biggest jump at Bristol called the "booter", and eventually I started to hit the jump as well. It is quite scary as it propels you tens of feet in the air and keeps you flying for multiple seconds, but it is completely safe all because of the landing. It is common knowledge that bending your knees can help reduce the impact of a fall or jump as impulse = Force x Time, so increasing the time of the impact decreases the force. The same applies for landing a jump on skis or a snowboard, but it gets to a point where you are so high in the air that just bending your knees will do little to help land the jump. For a jump straight up and down on a flat surface, the momentum right before the person hits the ground is equal to the impulse (change in momentum = impulse and momentum in y plane is going to 0 on a flat surface), so the velocity is proportional to force with the mass and time being constant, so the higher one jumps or is falling from, the larger the force of the impact will be. Imagine being 30-40 feet high. The force of the impact would be too large to handle even with bending your knees, yet ski jumps can propel people even higher and people land without injury all the time. This is because the landing of the ski jumps are angled downward, so the y component of the momentum is not becoming zero like it would on a flat surface, rather some of the skiers momentum in the y plane is conserved. Therefore, the change in momentum is decreased, so within the same landing time, the impact force is decreased. This doesn't seem like too big of a deal until you ever experience overshooting the landing to a jump, or coming up short and hitting the knuckle of the jump. From experience, I realize that overshooting a landing and hitting the flat surface (even if you are still on your feet) hurts more than failing to land the jump, but still falling on the landing.

As I may have mentioned before, I have an obsession with cars and specifically expensive cars. Growing up, the aesthetic appeal drew my attention, but as I now have my license it is a mixture of the ride as well as the beauty of the car (Yes, I still enjoy driving even in my minivan). Anyway, fast cars usually have an extreme look to them which serves two purposes. First, it makes sure people know you spent a ton of money on the car, but also it functions as a way for the car to generate downforce and therefore go faster. Downforce in the realm of car racing refers to the force the car pushes against the road underneath it, which means that the downforce is the normal force as well. Since the force of friction is the product of the normal force and the coefficient of friction, a higher downforce will create a greater frictional force between the car and the road, which prevents the car from sliding in corners (allowing the driver to take corners faster). Downforce also helps on straight sections of the racetrack as the greater frictional force allows the tires stay spinning, without slipping or burning out. Basically, downforce gives the car more traction, keeping it tight to the road. One simple method of increasing downforce is adding rear wings and spoilers, as the air rushing over the angled spoiler pushes the car down onto the road. Companies such as Lamborghini and Mclaren have adapted to increase the efficiency of their cars by having wings and spoilers that actually come out of the shell of the car at certain high speeds. F1 racing cars can actually provide up to a maxiumum of 5 times their weight in downforce, and most of that work is done by the wings (front and rear) and the diffuser. The diffuser works by going at the back rear of the car and converting the high velocity, low pressure air from underneath the car into low velocity, high pressure air at the rear of the car, creating a vacuum effect due to the Venturi effect. This extremely low pressure underneath the car in comparison to the higher pressure above the car creates even more downforce, making diffusers essential to F! racing and other sportscars. A very basic way to look at it is that fast cars are designed opposite of airplanes: airplanes' wings are designed to create lift and keep the airplane suspended in the air at high speeds, while cars are designed with negative lift (downforce) to keep the car on the road with as much traction as possible. In the video you can see just how fast the F1 cars can go around corners due to this downforce. Often, engine specifications and horsepower are seen as the reason for the speed of a car, but in reality a v8 can go faster than a v12 and vice versa because a large factor is balancing the downforce and the drag to maximize speed in corners and straight sections, which is why the design of a car's aerodynamics and small parts such as diffusers are so important.

I'm not sure if I "blogged" this in the right spot, but this is the opening blog post for physics c, approximately 1 of 40. I had homeroom in the physics room in 9th grade before the school rightfully realized how useless homeroom was (I had to walk from 3rd floor of IHS to far side of Dake for french 1st period). Anyway, I enjoy hanging out with my friends, camping, playing sports (soccer, lacrosse and CYO basketball) and snapchatting in my free time and one could describe my snapchat game as "fire" due to the quality and quantity of the images. I need to try to focus on improving my organization and time management this year, specifically in this class (and Calc) because I have a habit of procrastinating. Also, hopefully this course will help me decide what I want to do with my life because I literally have no idea. Ideally, I'd be super rich and be able to buy a ton of cars as I'm a bit obsessed, but at the very least I'd like to be happy. I'm taking Physics C because I enjoy math and science, but have no idea what I want to do for sure and because the physics last year was pretty fun. Hopefully this class is very math based because I prefer working with actual numbers than all of the weird things that were on the AP exam. At the end of the year, I hope to not only score well on both AP tests, but also have a better idea on what I want to do in college and for the rest of my life. Th style of the class seems like a good way to end my procrastination and prepare for college as well. I'm not sure what I am most excited about in Physics C this year, but for senior year in general, I just want to make the most of it and end high school on a positive note. I am probably most anxious for the unit tests in physics and calc because I know they are going to be a lot harder than anything I have ever experienced, but I just do not know what to expect. To clear things up about my username, I did not know what to choose and due to the inability to use characters besides letters, I settled on this basic name because IVIR Great was my hero growing up. -Back corner kid

Great insight!

Hi

I used to actually be obsessed with horses in my younger years and my favorite NFL team is the Denver Broncos.