Physics @tbans-blog - Tumblr Blog

Hard at work on our bridge. Trying to perfect the arched road deck we plan to use in the design.

Winter Classic 2012! Let's go Rangers!

While this is not a picture of the kind of mechanic efficiency in the sense that we discussed today in class, it is a bit of comic relief. The actual measure of mechanical efficiency comes from dividing the actual mechanical advantage by the ideal one, which are calculated by dividing the “out force” by the “in” one, and the “in distance” by the “out” one, respectively.

iprep

I would have to agree with Tom on his description of the measure of mechanical efficiency. His picture of the local government efficiency machine wouldn’t look so organized and thought-out as compared to our government today.

tbans-blog

Satirical and scientifically relevant. We can always count on TMT for a clever posting.

This video provides a visual representation of some of the concepts we covered in class!

Pulleys

This week in class we discussed the last lab we conducted. The lab was meant to demonstrate the concepts of AMA, IMA, and Efficiency with respect to pulleys. In our discussion of the lab we noted that in order to do the same work one could decrease the distance if the force was increased and the inverse was also true.

Ideal Mechanical Advantage, Actual Mechanical Advantage, Efficiency, Oh My!

In physics class this past week we discussed these three terms:

Ideal Mechanical Advantage is equal to the effort distance divided by the resistance distance. In short, d in divided by d out.

Actual Mechanical Advantage is equal to the force put out of a system divided by the force put into a system.

Efficiency is equal to the work put out of a system divided by the work put into a system. In other words AMA/IMA

*It is important to remember that when solving for these values that no units are required. AMA, IMA, and efficiency are all ratios.

letsgethonorsphysical-blog

I forgot to post this as part of my conservation of energy post, but this is some really quality physics right here. I think it’s really cool how everything just comes together. Like, you’re given enough variables to figure out a few unknowns, and there are so many equations you can use to find those unknowns. Yeah, it’s cool, I said it.

tbans-blog

You know what Nick- it is cool. After all, a day without physics is like a day without sunshine.

Today in physics class we discussed machines. This was a continuation of the work we did in the lab this past friday. Sadly, we did not get to watch this commercial. Essentially, a machine is a device that either increases a force or changes the direction of a force.

physicsphilosophizer-blog

Wow! Now that’s a lot of horsepower! With all this talk about power and horsepower, I thought it would be interesting to find out where exactly did the term horsepower come from. It turns out, it actually did have to do with horses. Scottish engineer, James Watt devised a unit of measure to relate to power that a car had with the power a horse had. This was of course done in hopes to convince people to buy his mechanical products. Whatever his methods, it seems that his term has stuck way past the time of horse-drawn carriages.

I know we covered horsepower some time ago but I couldn't help reposting this picture. Funny thing is, this is the exact car I plan on driving to school as soon as I get my license.

lukeypotatoes

Here is a simple picture of the one they call “THE HAWK” hunting with his bow and arrow. This bow has a lot of potential energy stored with it. There is also Gravitational Potential energy which is the work that was required to elevate the object against gravity. The formula of that is PEg=mgh. Potential energy and kinetic energy both play important roles with each other.

ionaphysics-blog

But can he hit the target

Wow. Billy has two bears, two deer, and a fox in his yard all at the same time! Talk about a coincidence!

In class this week, we touched briefly on the topic of chemical potential energy. Mr. Love explained that chemical potential energy is present in the bonds between molecules. Imagine the chemical potential energy present in the explosives used in this Mythbusters video!

To continue with the Warner Brothers theme, this video illustrates the idea of conservation of energy. Like mass or momentum, energy cannot be created or destroyed, it is simply transformed. Therefore, the sum of PE and KE remains the same for all positions in a system. When standing on the edge of the cliff, Wile E. Coyote has potential energy, and 0 kinetic energy. As he falls, his potential energy is converted to kinetic energy until just before he hits the ground, all of his energy is kinetic.

This week in class we learned about gravitational potential energy. Potential energy is energy in a stored state. It is calculated by multiplying height, mass, and gravity. The image above is an example of potential energy. The anvil possesses energy in a stored state. If we assume that the mass of the anvil is 500kg and it is suspended at a height of 100m it's potential energy would equal 50,000J.

All this talk of work reminds me of something my elementary school textbook once said. The introduction to the went something like this: You might say "Reading a complicated book is hard work!" However, a scientist might respond "Well, that depends." You would reply "On what?" He would say "On how many times you had to turn the pages."

I don't know why, but I never forgot that fictional discussion from my sixth grade textbook. It always bothered me that the scientist had to twist such an inane comment to into an annoying conversation starter. Anyway, it does provide a clear differentiation between the colloquial and scientific definitions of the word "work." In everyday speech, we define work as anything difficult or tedious whether it be physical or mental. In science, work is the product of the force exerted on an object and the distance travelled.

taylorgangorphysics-blog

I find it funny that certain things in Physics that we’ve come to learn as fact are contrary to what we originally thought. This really began with Centripetal motion, which was a counter-intuitive concept to all of us; and this is the same thing as work, which we originally perceived as being the same thing as force, but is in fact the combination of a force, and the resulting motion.

I also find it interesting how seemingly counterintuitive these concepts can be. However, when we come to fully understand them we realize that the concepts we explore in Physics class provide fuller explanations for the phenomena we observe. What makes physics so great is that there is definitely a connection between what we see and what we learn. In physics, as in life, it's all a matter of perspective!

Today's Test

Today, December 7th, we had a Physics test. The test covered multiple topics, namely momentum and work. I felt confident in my knowledge of the material until I reached one question. The second short answer question on the final page of the test posed a question regarding force. The question stated that a 70kg hockey player was struck by a 0.10kg puck which exerted a force of 50N on the player. The problem then asked to determine the magnitude of the force exerted on the puck by the player. I attempted to solve the problem with every formula I knew to no avail. It was then I realized that the force the puck exerted on the player and the force the player exerted on the puck were the same, just in different directions. The answer to the question was -50N!

Yeah buddy!!!

Today in physics class we performed a lab regarding work. Each student in the class ran up the stairs like Jesse here. These times were recorded, and using the students' weight in Newtons we calculated how much "work" was done.

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