Welcome to the Fall 2016 Physics 111 blogspot!

Welcome to (or back to) the Physics 111 blog! It is now Fall of 2016 and some of Colgate University's Fundamental Physics I (Physics 111) students will soon be posting short summaries/descriptions relating news, art, music, etc. to physics. By reading this blog (and commenting/participating), we hope that, as always, you will see that physics is found in all facets of life and is not relegated to projectile motion and spherical cows.

Hoverboards: Are we there yet?

As the year of 2015 draws to a close, many fans of the beloved classic, Back to the Future, bemoan the fact that in 2015 we have not created all of the wonderful inventions that had been promised via Marty McFly's adventures. However, I did some digging and found some very promising prospects on the creation of a hoverboard. Three types of hovercraft, that actually function as we would a hoverboard would, are currently on the market. Two of these hovercraft, the Hendo and Lexus, rely on magnetic fields for the source of repulsion necessary to overcome the force of gravity. The other hovercraft works like a small helicopter, using thrust generated by blades moving air at a high speed.

In a quick calculation I determined how much force would be necessary for a hoverboard to lift a person off of the ground. For a person weighing 70 kg to stand on a 5kg hoverboard, their force due to weight would be about 735 N. In order to lift that person into the air, the force provided by the craft must be more than 735 N.

The other option for a "hoverboard" comes from the self balancing motorized scooter. It works using pressure plates, infrared detectors, and a gyroscope. By adjusting the rpm and angle of the wheels based on the movement of the person standing on the board, the "hoverboard" allows the person to move about without handles or any outside force exerted by themselves. The issue with these is that since the "hoverboards" are so popular in demand there has been an increase in their cheap manufacture, which leads to the use of cheap parts. Since lithium batteries are now being produced cheaply (and poorly), these cheaply produces "hoverboards" are provided cheap lithium batteries that are more prone to short circuit and combustion. For this reason, these boards have been banned from airports.

So maybe we haven't perfected the hoverboard yet, but we seem to be on the path to creating a cool new way to travel!

http://www.detroitnews.com/story/business/autos/chrysler/2015/11/27/viper-acrs-record-shattering-tour/76476364/

            In this article, there is a discussion of the new Dodge Viper ACR, and how recently it has been decimating lap times of super and hyper cars supposedly much out of its leagues. It has been decimating records held by the top Porsches, Lamborghinis, Ferraris, etc. This is quite impressive due to the fact that one of these fine cars could be yours for more than half the price of the previously mentioned vehicles. What makes this car so effective?

            The ACR has one of the most advanced aerodynamic systems ever designed on a performance car to this date. It generates a tremendous amount of down force which is the key to its success. This down force created means that the air that passes over the car is channeled in such a way that it pushes the vehicle, specifically the rear wheels where the power is generated, into the road. This allows for more grip and more friction with the rear tires which means that more of the power made by the engine will be able to be transferred to the road. Also, this increase in proper air flow allows for better cornering and handling as well, which too would improve lap times.

http://www.indiancarsbikes.in/auto-news/inferno-exotic-car-the-first-mexican-hypercar-136562/

            In this article, there is discussion of a new ‘Hyper Car’ in the works, coming from Mexico. The new car called the “Inferno” with a very impressive claimed 1,400 horsepower, a top speed of 245 miles per hour, and arguably most impressively a 0-100km/hr time sprint in the sub three second period. These are very astounding numbers in the automotive performance world. What is most interesting about this car however is the material it is made out of. Supposedly the Inferno is composed of a body made of a “metal foam,” which is comprised of a mixture of silver, aluminium and zinc. This is supposedly an astoundingly light yet still strong compound.

            The physics behind this come from the performance figures. I believe that this cars extremely impressive statistics are due in most part to the ultra light composition of the body. That coupled with an engine that produces a massive amount of force, it is not surprising that is putting up statistics that only the top 5% of sports cars make. It will be interesting to see a fully produced model once they are off the line.

Steamy noodles

Since I'm really not creative when I'm cooking, I often resort to making pasta for dinner. As I drain the noodles, a huge rush of steam comes pouring out and is extremely hot and super painful, leading to a depressing mess of noodles in the sink. Having just learned about latent heat, I decided to look up whether steam burns, of which I have been vaguely warned by my mother when desperately trying to teach me how to cook, can be worse than just water burns. Because I have definitely had steam burns that seem to hurt much more than spilling tea or coffee on myself.

It turns out that in fact steam burns can be much hotter, and therefore much more severe than water burns. Since the heat in steam can be increasing while the state of matter doesn't change, it can get much hotter than just the minimum temperature to get to the gas state. Steam can be hotter than water, and in this case the noodle water happened to be boiling. So it can potentially get quite painful without you even knowing it.

Moral of the story: Be careful with ya noodles, everyone.

Bear on a tightrope

I saw this video on YouTube and was fascinated by it.

The bear and the person can move on the thin rope due to the large moment of inertia created by the huge mass of the bear and person.Assuming the mass of the person is 70 kg, the bike 180 kg and the bear, 200 kg with a height of 1m. Assume the person is 3m away from the tightrope. If they are both treated as point masses, the moment of inertia will be;

I = 70(3^2) + (100+180) (1^2) = 910 kgm^2

This is a large moment of inertia and would help keep the system in balance so it does not topple over.

Leaf blower

I found this exploring the internet and decided to figure out the man's top speed before he falls. He appears to have reached his top speed after seven rotations in 4.5 seconds. I approximate the chair to have a diameter of about half a meter, so r=0.025m. Since circumference = 2(pi)r, he rotates seven times, and Δl = rΔtheta, Δtheta = 44.8 rad. From this, I can use kinematics to find the angular velocity. Thetaf = 0.5at^2 + w0t + theta0 --> a (angular acceleration) = 4.42 rad/s^2. wf = w0 + at --> wf = 19.89 rad/s which is 3.17 rev/s