Uncategorized

Physics of Brazilian Jiu-Jitsu

alexr2015

Inquiry Question: How does a Brazilian Jiu-Jitsu practitioner’s understanding of physics make him or her more effective?

Jiu Jitsu is the gentle art. While you do end up breaking peoples bones, it’s the fact that you don’t need 8-inch diameter biceps to beat someone. You actually use their own body against them, through the power of phyiscs ooooooh. By using their own body weight and momentum, you can throw them around, over your body, and have them in a choke. You use forces of gravity, momentum, and other physics to grapple your opponent and send them into an armbar, kneebar, or a number of other chokes and holds.

We examine this fighting style today because the moves that Jiu-Jitsu artists train lie firmly in physics, more specifically, torque and momentum. In the case of an armbar, you use the persons joints and arm against them, and you use your legs as a fulcrum, essentially magnifying the amount of force you can exert on your opponent’s arm.

A kneebar works the same way. You use your legs as the pivot point, and their leg is the fulcrum. Pushing sideways relative to the knee inflicts major pain on the opponent, and your knowledge of physics, more specifically, the pivot point you make with your legs, increases your effective stopping power.

Say you’re a relatively small person fighting a much larger person. Using your knowledge of physics, you know the large man’s center of gravity is much more higher up. You can use this to send him to the ground faster, as the old saying goes, “The bigger they are, the harder they fall.” Once on the ground, take their knee or arm and get them into one of these holds, or a number of other ones and utilize your knowledge of torque and fulcrums to make him cry uncle.

Review of Edublog Plugins

alexr2015

Today, I’m reviewing three plugins that Edublog offers.

Embed Any Document is easily one of my favourite plugins to use. This plugin simplifies the process of uploading and embedding a document of your choice, word docs, powerpoint presentations, you name it. You can upload documents from your laptop, from a URL, from Dropbox or Google Drive. For me, the plugin has almost never not worked, it’s very reliable. I love it, and it’s a must for any student at Riverside who often uploads to their Edublog.

The Tag Cloud also seems to be a favourite for a lot of my peers, as it wonderfully organizes your tags, categories, or both into a neat little cloud for you to rotate to your leisure. At least, that’s what it’s advertised it does. In reality, it simply lists your tags and categories. The more often you use said tags or categories, the bigger they are on the cloud/wall. Unfortunately, I could not get this plugin to work. Documentation for this plugin is also not available, as requesting it on the plugins page leads to a dead link. My view on this plugin; if you’re a function over form kind of guy or gal, why not have it on your blog?

 

Math 10 Week #10

alexr2015

We continued our polynomial unit this week. An important concept that we covered recently was division with polynomials. We’ve added, subtracted, and multiplied polynomials, but we haven’t divided. With polynomials, it’s not called division, it’s called factorization. We’ve factored before, but that was with only single numbers. This time it’s with polynomials.

In the first question, you can factor out a x, because there is an x in both terms. So the x factored out, and is placed on the outside of the brackets. In the second question, you can factor out a 2 from both terms, so the equation goes from 4x+6 to 2(2x+3).

 

Math 10 Week #8

alexr2015

We wrapped up our Trig unit this week with a test, and start talking about polynomials. We learned a number of things regarding polynomials. We learned about different types of polynomials, and identifying coefficients.

A coefficient is a number beside a variable. 4y actually means 4 times y. 4 is the coefficient.

There are four types of polynomials: Monomial, binomial, trinomial, and polynomial.

A monomial will only have one term: 4x, 9y, 12, 2, 1

A binomials will have two terms: 4x-5, 2x+3, 3y-9

A trinomial will have three terms x^{2}-4+4

Polynomials can have four or more terms: x+y+z+2, 2a-b+5c+9

 

 

Math 10 Week #7

alexr2015

We were introduced to the concept of Trigonometry this week. We also learned about three buttons on the calculator. sin, cos, and tan. These words are actually shortened, and they mean “sine, cosine, and tangent”. Trigonometry will usually involve right triangles, but isosceles and scalene triangle are able to be solved through trigonometry. Trig questions usually ask for the length of one side of a triangle, while giving you a reference angle, along with the length of a single side.

How do we solve these? First, each side has a specific name, depending on where the reference angle is. The names are adjacent, opposite, and hypotenuse. The hypotenuse will always be the line opposite from the right angle. The adjacent line is the line closest to the reference angle that is not the hypotenuse. The opposite line is the line farthest from the reference angle that is not the hypotenuse. Got it? Good.

You’ll have to learn the phrase SOH CAH TOA. The beginning of each word represents some specific buttons on the calculator, namely sin, cos, and tan. The last two letters of each word represent the lines of a triangle. You remember “Adjacent, Opposite, and Hypotenuse”, correct? If you have to solve for the length of the opposite line, and are given the length of the hypotenuse along with a reference angle, the question is a sine question. Sine(reference angle)=\frac {O}{H} If say, you were given the length of the opposite line along with a reference angle, but not the length of the hypotenuse, then the question would look like: sine(reference angle)=\frac {O}{H}

The best way to figure out what sort of trig question lays in front of you is to remember the phrase SOH CAH TOA.

Now take a look at some of these questions below. All problems require you to solve for x. The first one is a sine question. How do we know? The opposite line is represented by x, while the hypotenuse is represented by 7. The reference angle is 27. The equation is sin27={x}{7}. We multiply the equation on both sides by 7 to isolate x. The equation now looks like 7(sin27)=x.
7 multiplied by sin27 (approx. 0.454) is 3.2.

The opposite line is 3.2 units long.

Float Your Boat!

alexr2015
  1. We tried to discover what design would hold the most pennies.
  2. If we had more air pockets at the bottom of the boat, then they boat would have more buoyancy, letting us hold more pennies because more air pockets translates to more buoyancy.
  3. Our boat held 57 pennies.
  4. We created an air pocket at the bottom of the boat in an attempt to give the boat more buoyancy.
  5. I would ditch the straws and popsicle sticks at the bottom of the boat.