# IVIR GREAT's Physics

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## Jenga

This past weekend, I saw a giant game of Jenga at MIT. Literally. The blocks were nearly 2x4s, and the structure was taller than I am. While I did not stay to watch, it is interesting to think about a few of the different strategies that I remember from my childhood days. First of all, I used to believe that the faster you pulled the object out, the less chance a collapse would occur. While I'm not sure of my logic behind this reasoning, I most likely imagined that hopefully the structure just w

## Horsepower

Cars, especially sports cars, often have their horsepower compared as a somewhat ignorant method to determining the faster car. However, this is not the most accurate way of making judgement because there are other variables, some much more important, in determining a cars acceleration or top speed. While an engine's horsepower provides the force, accelerating the car, it is important to remember the basic fact that F=ma. Therefore, a 4000 lb car with twice as much horsepower as a 2000 lb car wi

## Second Bounce

Have you ever dropped a ball and had it bounce once normally before taking a crazy second bounce? I'm always watching out for this phenomenon when I have a lacrosse ball on a hard surface, but I've never really understood what was going in. The main factor causing the crazy second bounce is actually the spin on the ball acquired during the first bounce. As the ball falls, it usually has a small amount of spin or is traveling at an angle that isn't 90 degrees. As the ball hits the ground, the ide

In the past few years, Madden NFL video games have adopted real time physics, an extremely complicated technology that allows the players in the game to react according the actual physics. In previous Maddens, a spin move would result in one of four tackles, and there were only about 10 different types of tackles, making the end of plays appear too staged. However, real time physics enables the characters in the video game to react to a force from an opposing player as they would in real life, c

## Frisbee

The simple art of Kan Jam or any other frisbee related game seems skills based, but it may help to have knowledge on the physics of the flight as well. The first aspect of a frisbee is the design. Most frisbees are relatively thin with curved edges, which make it more aerodynamic, creating lift while in flight. Similarly to cars, the curved shape at the front of the frisbee allows for air to pass over the frisbee faster than air passing under it, making the air above the frisbee at a lower press

## Shape and Dolphins

It is not surprising that shape has a lot to do with the movement and speed of objects, but it may be surprising that dolphins pose such a question to researchers when it comes to their advanced swimming techniques. The shape of an object can determine numerous factors of an object that are integral to its performance. For example, race-cars are built with a specific shape in order to produce high amounts of downforce while airplaines are built with their wings in order to create lift when pierc

## BMX

As usual, I found myself watching quite a bit of YouTube over break, especially different BMX videos. While I could only dream of pulling off the tricks the professionals do, watching it makes me feel nervous as I realize the potential consequences of a nasty fall. I have kind of a lot of blogs on landings/falling, so I figure I will use this blog to tackle one of the most crazy things a bmx rider will do: grind a downward sloping railing on one peg. For those not extremely comfortable with BMX

## Turf: the good, the bad, the ugly

Playing sports in high school, you start to look forward to any opportunities to leave the swampy grass for the fresh turf field. Since Pinegrove fields are uneven, rocky and often have large spots of grass missing, the turf is always a better option. However, playing on turf does not always end well for a variety of reasons. The good: traction. Turf provides excellent traction as it increases the coefficient of friction between the ground and cleats, enabling for sharp movements. On grass,

## Boxing vs UFC

Boxing and UFC are both entertaining (when there are available without the astronomical pay-per-view prices), but the physics of each one is pretty different. If anything, UFC is a more dangerous sport, making boxing look like a children's show. The major difference is due to the different types of gloves used in each one. Boxing gloves are pretty well known, but I've included pictures of both types below to make the comparison easier. While boxing gloves have quite a bit of padding, UFC gloves

## Tire Swing

Growing up, my best friend had a tire swing in his backyard. While it provided trivial entertainment, looking back, a tire swing involves quite a bit of physics. First of all, there is the connection to the tree. The swing needs to be far enough away from the base of the tree in order to prevent accidental collisions, but it also needs to be sturdy enough to withstand human weight. The further out from the base of the tree you put the swing, the more torque that is applied to the branch as the l

## Snow and Rain

Since we learn that objects consistently gain velocity in free fall motion due to the acceleration of gravity at 10 m/s^2, why doesn't rain and snow wreck havoc since it is falling from an insanely high distance? One reason for this lack of speed, especially with snowfall, is because of air resistance and drag forces. The net force on a snowflake would be the weight (mg) minus the drag forces acting on that object. Since snowflakes are relatively porous and non-aerodynamically shaped, the drag f

## Helmet to Helmet collisions

In the great game the Denver Broncos happened to win, there was a critical personal foul called in which a Denver player blasted the New England receiver shortly after the receiver caught the ball, incidentally hitting the receiver helmet to helmet. Considering that the average NFL player can run 15-20 mph and weighs around 200 pounds (90 kg), that is a lot of linear momentum that the receiver is being hit with. When the player is hit, a lot of the energy is dissipated as the players come to res

## Lets Go Broncos!

Since I'm sure everybody is watching the Denver Broncos vs. New England Patriots game right now (its currently halftime), I'm sure many of you are thinking how could the Patriots miss an extra point. Well, if you are curious, visit my previous blog on field goal kicking. More importantly, I'm sure some of you are like me, nervous due to Peyton Manning's lack of throwing ability in his old age. After his neck surgery, and since he is approaching 40, his arm strength is decreasing, requiring him t

## Trampoline Limits

A trampoline is a great example of spring potential energy and a restoring force, but it also brings up another question: why is there a 'maximum' height and why can you "double bounce" someone to make them fly higher than that maximum height. As a person begins jumping on a trampoline, their kinetic energy is converted to spring potential energy when they contact the trampoline, and then converted back to kinetic and gravitational potential energy as the person leaves the trampoline towards the

## Bulletproof Glass

As it turns out, the physics behind the ability of bulletproof glass to stop the momentum of a bullet without shattering is in fact a lot of chemistry. However, this makes a lot of sense considering that a large portion of chemistry is simple physics applied on the microscopic scale. A bullet typical travels 400 meters per second, which creates a large momentum despite the fact that the bullet is only a few grams. Normal glass is relatively fragile, shattering upon impact of most bullets while s

## Stealth Bomber

The B-2 bomber, commonly known as the Stealth Bomber, is an extremely expensive military aircraft capable over flying undetected across the globe. First of all, the bomber can travel over 6,000 miles without refueling due to its aerodynamic shape. The entire aircraft acts as a singular wing, due to its "flat" shape, which allows the resistance from air to hit the slightly angled bottom and push the aircraft up against the force of gravity. Since the aircraft can almost travel at the speed of sou

## Drifting-Without snow

People have started to worry about the roads in Rochester as a thin coating of snow, or ice, can cause cars to start sliding due to the lower coefficient of friction between rubber and ice rather than rubber and asphalt. This sensation, although scary for most drivers, is often sought after by drifting. Drifting is the process of purposefully kicking out the back-end of a car around a turn, for the thrill and awesomeness, an then corralling the car as the driver comes out of the turn. Although o

## The Slapshot

In honor of my Ovechkin's 500th goal (my favorite player on my favorite team), I decided to look into the physics behind the infamous slapshot in hockey.  The basic physics of the slapshot include the windup that produces torque applied to the puck and the transfer of energy to the puck, but there is a lot more physics involved that launches the puck with such a high velocity. First of all, the collision with the puck is mostly elastic, but considering the huge noise produced during a shot,

## Snowboarding Rotation

In the winter, my favorite outdoor activity is snowboarding and sometimes, I get a little too reckless. However, this post will go through the physics of a simple 360 in the air on a snowboard, which can be applied to skis as well.  The first important part in landing a 360 is making sure you can hit the jump with the perfect speed to clear the "table" part and land on the actual landing. This is critical because if you under/undershoot the landing, you will most likely fall due to the phys

## Physics of Field Goal

Since Brandon McManus and the Denver defense just rescued the aging Manning's playoff hopes, I thought I'd celebrate the victory with a blog post about the physics of the NFL field goal.  The field goal post is 10 feet high, so the necessary vertical displacement is around 3 meters. The width of the field goal posts is about 5.6 meters. For an average NFL field goal, lets assume the kicker kicks the ball at a 45 degree angle. (Angle is greater for shorter field goals, but smaller for longer

## Why we don't (or do?) fall

Walking may be one of the most underestimated phenomenons in the modern world as the simple act is done effortlessly by nearly every able human alive. When walking, the foot is planted into place since the force of friction between the foot or the shoe and the ground stops the foots velocity in the x-direction. Once the front foot is planted, the back foot is able to push off the ground, causing the normal force to push back against the foot and allow you to keep walking forward. While running,

## Barrett .50 cal

I have always been fascinated with the mechanics of different types of guns, and since the impulse test was Tuesday, it is a good time to look at one of the more common questions surrounding "explosion" type collisions. One of the most powerful weapons is the Barrett .50 Caliber Sniper Rifle. Although there are multiple types of bullets used, an armor piercing bullet for a .50 cal is around 45.8 grams (just the projected portion), which is .0458kg. The bullet leaves the barrel of the rifle at sp

## Phone crack part 2

After reading Zach's blog post on a phone cracking, I started thinking about the one thing I have been doing since I got my first cell phone to prevent it from cracking: kicking it.  I usually try to catch the phone on my foot or at least slow its fall, but it is interesting to actually think about the advantage of doing so due to the physics behind the phone's fall and impact with any surface. First of all, the best way to prevent a falling phone from cracking is by trying to catch it with

## #LaxBro

As fall lacrosse is starting to end (last tournament this Saturday), I decided to think about the physics behind the sport I love.  The first thing that comes to mind that involves a variety of physics factors in lacrosse is the shot. One of the most important factors in a successful lacrosse shot is the legs. First of all, since the body is rotating extremely fast during a lacrosse shot, in order to aim successfully, you have to keep your feet pointed towards the target in order to release

## Darts

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'

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