Period 7- 11/24

The first thing we did today was take our 4th re-assessment on vectors. One question had to do with the "Angle of Attack" of a helicopter. You can read more about that subject here; http://www.copters.com/aero/angle_of_attack.html

Next we started to go over the lab. One of the big ideas that we found was that Gravitational Force = Mass x Gravitational Field Vector. Also, we found through our testing that there are 10N for every Kilogram.

After we dove into these ideas, we got into a discussion about elastic forces and the differences in force between small springs such as springs from a pen or a slinky, and also, large springs such as the shocks on a car.

-Tripp

LHC is on!

THe LHC produced the first collisions of protons today.

11/19 class

At the begining of class we took a reassessment on how to find the forces exerted by an object through a free body diagram. After this we had a talk about how we shouldn't just take reassessments over and over. then we went over the motion in two dimensions work sheet that we worked on for homework. an important idea we learned was for a car moving around a curve if the angle between the acceleration and the instanttanious is greater then 90 degrees and is changing direction the car will be slowing down. When the angle is equal to 90 degrees the the car will be moving at a constant speed. when the angle formed is less than 90 degrees the car will have an increasing speed. it is key to remember to the vector of the car's direction is tangent to the curve or circle.

Gamma Ray Satellite may have found dark matter

Here's another great post that describes a recent discovery of what may be dark matter, which makes up 20% of our universe (regular matter is only 4%).

The excess gamma rays could possibly be coming from a hypothesized dark matter called Weakly Interacting Massive Particles (WIMPs), colliding with one another and annihilating themselves into pure energy.

Fermi may have spotted dark matter.

Station 8 Review (Written by Zack H.)

We reviewed station 8. In station 8 we measured the angles and the force of the string and the spring ‎scale and and found the angles to find the mass of the mass. With the angles and forces we found , we ‎were able to find the missing force using vector addition. We learned that when adding vectors you ‎also have to take into account the angles. Unless the angles are in the same direction you can’t use ‎simple math to add them up This explains Mr. Burk’s point in class that one plus one does not always ‎equal two.‎

Want to conquer stress? Exercise is key

Here's a great article from the NYT about a new study on rats showing that exercise allows our brains to better handle stress.

Here's a quote:

It looks more and more like the positive stress of exercise prepares cells and structures and pathways within the brain so that they’re more equipped to handle stress in other forms,” says Michael Hopkins, a graduate student affiliated with the Neurobiology of Learning and Memory Laboratory at Dartmouth, who has been studying how exercise differently affects thinking and emotion. “It’s pretty amazing, really, that you can get this translation from the realm of purely physical stresses to the realm of psychological stressors.

Posterous: another super cool tool!

Have you ever wanted to share a file, mp3, photo, or video without having to email everyone, or post an elaborate facebook status? Perhaps you have some great notes you want to share on the blog.

Well, here's the solution.

Just send an email to post@posterous.com, and attach whatever it is you want to share. Posterous will send you a link to the website you created with that attachment.

It couldn't be easier.

great career advice from the creator of dilbert

Scott Adams, the creator of Dilbert, has a wonderful post on his blog with some great career advice.

Here's a quote:

If you want an average successful life, it doesn’t take much planning. Just stay out of trouble, go to school, and apply for jobs you might like. But if you want something extraordinary, you have two paths:

1. Become the best at one specific thing.

2. Become very good (top 25%) at two or more things.

The first strategy is difficult to the point of near impossibility. Few people will ever play in the NBA or make a platinum album. I don’t recommend anyone even try.

The second strategy is fairly easy. Everyone has at least a few areas in which they could be in the top 25% with some effort. In my case, I can draw better than most people, but I’m hardly an artist. And I’m not any funnier than the average standup comedian who never makes it big, but I’m funnier than most people. The magic is that few people can draw well and write jokes. It’s the combination of the two that makes what I do so rare. And when you add in my business background, suddenly I had a topic that few cartoonists could hope to understand without living it.

Suddenly, becoming extraodinary doesn't sound so hard.

FAILCON: a conference dedicated to failing

It turns out that in the business world, just like the rest of like, of the of keys to great success is failing often and learning from one's mistakes. It can literally be worth billions. Good thing they now have a conference to teach you how...

Thursday's Class, 11/12/09

We started out class talking about quantity vs. quality. We decided that it is better to specialize in one topic than to be decent in many topics. We also discussed FARMIPS and what really qualifies as a FARMIP. We concluded that you can't simply just turn in old reassessments or corrections, you have to gain insight on the concepts by studying them a little bit. Then, we looked at MOP 40, the homework from the last couple of nights on vector subtraction. We looked at this in depth and explained every problem. In fact, our homework for tonight is to make sure we understand the three problems from MOP 40.

Physics Jokes!

A neutron walked into a bar and asked, "How much for a drink?" The bartender replied, "For you, no charge."

What did one quantum physicist say when he wanted to fight another quantum physicist?
Let me atom.

Anything that doesn't matter has no mass.

What did the male magnet say to the female magnet?
From your backside, I thought you were repulsive. However after seeing you from the front, I find you rather attractive.

Why did the chicken cross the road?
Isaac Newton: Chickens at rest tend to stay at rest, while chickens in motion tend to cross roads.

Why did the chicken cross the road?
Albert Einstein: Whether the chicken crossed the road or the road crossed the chicken depends on your frame of reference.

Mr. Burk, I think Anne Louise and I deserve a propsicle for this one.

November 11, 2009 Veteran's Day

At the beginning of class, we took a reassessment which covered concepts from both chapters 2 and 3. We were to turn in the lab station notes. We were given back the graded vector activity lab. We were also given a sheet with concept 2.5.4(Given a velocity vs time graph, can you write a mathematical model to describe the motion?) for reassessing and a the "Motion in Two Dimensions" lab. The main discussion throughout class was about adding and subtracting vectors. We looked over the sheet "More Vector Math" to get practice. Afterwards, we got started on the "Motion in Two Dimensions" lab. Overall, it was a great class.

Will the world end in 2012?

Answer: No.

Read for a thorough debunking of this pseudoscientific meme that is percolating through popular culture.

station 3

in station 3 there were two models set up. The first on is a cart on wheels in rest with two ropes pulling an equal horizotal force on both sides. the other model is a cart not on wheels with two different horizonal forces. they both have a net force of zero the second model is at rest because both sides are equal because of frictional force of the track on the cart so it is at rest.both of these models have a displacement of zero.

Station 4

For Station 4, a mass hung motionless from two spring scales supporting it from each side. It was connected to the cabinet. The spring scales read 3.7 and 3.8 N. After drawing a free body diagram and adding the vectors together, it created a triangle. With the S.S forces pointing NE and NW, the gravitational force was drawn south to close the figure with about 4.3 N. This made since because the mass was still causing the net force to be 0 N. I noticed that the mass actually was 3.7 N when measured, but on the FBD it was 4.3 N. This was fine though because I was close. Fractions of an angle difference could cause this, so it was fairly accurate.

Anna hawkins - station 7!

I did station seven and the whole gist of this lab was that there was a fan cart on a ramp with a 7 degree incline. The fan would only remain stationary if the fan was on a high enough level. The higher the incline, the faster the fan needed to be spinning. When the cart is stationary on the ramp the net force is zero, we know this because the net force is not accelerating. THere are three forces acting on the cart. The force of gravity on the earth was acting downward at a 270 degree angle. The force of the air is moving to the left at a 187 degree angle, and the normal force is acting upward at a 97 degree angle. Another reason that we know that the net force on this object is zero is because the three vectors(forces) all add up to equal zero.

Station 4

In this station, a mass was supported by two strings at different angles. The mass was stationary and therefore in constant velocity, so the net force acting on it must be zero. Since this is true, we know that the forces on the mass, the tension force of strings a and b on the mass and the gravitational force of the earth on the mass, must equal to zero. The tension forces could be easily measured, one had a magnitude of 3.8 Newtons and a direction of 145 degrees and the other was 3.7 Newtons and 30 degrees. To find the magnitude and direction of the third force, gravitational force, the known two forces must be added together using the head-to-tail method and the resultant vector will be the correct magnitude, but in the opposite direction. The third force turns out to be 4 Newtons and 270 degrees.

Report by Tripp

For this lab, I observed the station with the two ramps. The setup consisted of two ramps with a spinning wheel on the higher side of each, a string with one side tied to the cart or block, and the other side attached to a spring scale with weights on the non-spring side. Both ramps were sitting at about 10 degree angles. In order to keep the cart stationary, I had to adjust the weights on the spring scale. By doing this, I was making the Fnet = 0. The forces acting on the cart and block were, gravitational force, normal force, and frictional force.

The FBD for the block can be seen here

http://www.imaginationcubed.com/loader.php?aDrawingID=3fa371edd6e9a7c62f2706cd7384695d&from_email=thdgolfer%40gmail.com&from_name=Tripp

http://www.imaginationcubed.com/loader.php?aDrawingID=04d816b85920f9d2ab199716c0885a89&from_email=thdgolfer%40gmail.com&from_name=JoNNDluysdtiu

Station 4

Station 4 includes a mass and two spring scales. The spring scales are coming from separate angles and holding the mass. The net force has to equal zero because the mass has constant velocity, it isn't moving. The forces acting on the mass are the tension force of the first spring scale on the mass, the tension force of the second spring scale on the mass, and the gravitational force of the earth on the mass. The spring scale on one side read 3.8 N and the other read 3.7 N. The unknown vector was the gravitational vector. When the third vector is added to the other to quantities, taking into consideration not just magnitude, but also direction, the forces should add to be zero.

To see the free body diagram for this situation, go to: http://www.imaginationcubed.com/loader.php?aDrawingID=8992e1a1a7247c54eae0446dc7c7c2e7&from_email=caroline.hufford%40gmail.com&from_name=caroline

I tried the link and the drawing didn't turn out exactly the way that I had intentioned it to. The force on the upper right corner should read Ft, SS2 - M, and the bottom force should say Fg, E-M.

Station 6

Station 6 consists of two models. The first model is a spring scale attached to a string by the hook on top of the spring scale. The force that the spring scale is measuring is 0. Gravity is keeping the spring scale down, while the tension force of the string is keeping it up. The scale is at rest. The second model is a spring scale attached upside down so that the hook where the mass is usually put on is facing up instead of down. The force of gravity is pushing model two down. Keeping it up is a tension force of rope to hook. There is also a small elastic force expanding because of the spring scale and that is pushing the spring scale down.

Station 2

In this station, we examined the situation of a 5 kilogram mass on a force plate. We specifically looked at what forces were acting on the mass. The two forces acting on the mass were the normal force of the force plate going upwards and the gravitational force of the earth going downwards. We measured the normal force to be 50 Newtons, and since the object had constant velocity, the net force had to be zero. This means that the gravitational force also equals 50 Newtons. We then saw that as the incline increased, the magnitude of the normal force decreased and vice versa. I honestly tried as hard as I could to put a picture of my free body diagrams but I just couldn't find a way how to. In order for the net force to be zero (since the mass is not moving) when the incline is raised, there has to be another force that is equal to the normal force and at the same angle as the incline. That force is frictional. Since you know what the gravitational and normal forces' magnitudes were, you can find the size of the frictional force by having it make the net force equal to zero.

Also, I see that Zach posted something about this station right before I did. I was honestly almost done. I hope that's alright.

Station 2

In station 2, there was a scale on top of a track. I put a 20 N block on the scale when the scale was on flat ground. I then put a few books under one side of the track to put the track at a 10 degree angle. I put the 20 N block on now, the block showed up on the scale as only weighing 18.5 N. On a level track, there are only two forces working on the object, which is the gravitational force of the earth on the object and the normal force of the object on the earth. But when the angle is changed, another force is added. This is the frictional force of the track on the object. We know that the net force in both of these situations is zero, because the block is stationary.

Station 3

Station 3 involves two separate ramps, each with a car on it. Ramp one has a low friction cart with a spring scale and weight attached to each side. Both spring scales measured 2 N. The forces acting on this cart are the gravitational force of the earth on the cart, the normal force of the ramp on the car, and the two horizontal tension forces of the rope on the block.

Ramp two has a cart with a block under it (creating friction) with one attached spring scale measuring 2.2 N and the other measuring 3 N. Even though the two weight measurements are different, the car is still motionless. This is because the side with the small weight has a force of static friction acting on it, causing both sides of the cart to have equal amounts of force. The other forces acting on this car are the gravitational force f the earth on the block, the normal force of the block on the cart, and the horizontal tension forces of the rope on the cart. The net force of both cars is 0.

The online drawing of forces is at this link. http://www.imaginationcubed.com/loader.php?aDrawingID=276d17d61f25418ca856339574be9174&from_email=alanac1%40comcast.net&from_name=asdf

Thursdays Class

Thursdays class was very interesting. For the first half of class we talked about the importance of sleep and why we need it. We talked about how just the loss of one or two hours can decrease your ability to learn a lot. Some scientist did an experiment to test this theory. They told a certain number of 6th graders to stay up on night and another group to get a good night sleep. THe next day, the kids who had not gotten much sleep seemed to perform at around a 4th grade level compared to the other kids who got sleep performed at a 6th grade level. An average teenager around our age should be getting around 8 - 9 hours of sleep a night. Some interesting facts on how to get a better night sleep are to not drink caffeine after 4 p.m. and to make sure that you are not watching TV or looking at a computer screen an hour before you go to sleep.

Thursdays Class

Thursdays class was very interesting. For the first half of class we talked about the importance of sleep and why we need it. We talked about how just the loss of one or two hours can decrease your ability to learn a lot. Some scientist did an experiment to test this theory. They told a certain number of 6th graders to stay up on night and another group to get a good night sleep. THe next day, the kids who had not gotten much sleep seemed to perform at around a 4th grade level compared to the other kids who got sleep performed at a 6th grade level. An average teenager around our age should be getting around 8 - 9 hours of sleep a night. Some interesting facts on how to get a better night sleep are to not drink caffeine after 4 p.m. and to make sure that you are not watching TV or looking at a computer screen an hour before you go to sleep.

Station 7

There are several forces acting on the cart while it is on the track. They are: the downward gravitational force of the earth on the cart; the normal force of the track on the cart; and the force of the air on the cart. When the cart is on the right side of the track, the fan needsto be at a lower speed than it would need to be on the left side of the track. Thyis is because the slop eon the right side of the track is smaller than the slope on the left side of the track. You would need less air force on the right side of the track because their is less gravity acting on it. So the net forceshoudl be closer to zero if the force of the air and the force of gravity are closer in size. On the left side of the track, the fan should he at a higher speed, because there is a higher force of gravity acting on the cart, therefore we need the air force to be higher so they can be equal.

Sleep tips from the Mayo Clinic

Here are some great sleep tips

What is the best study break? Taking a walk in the woods

Scientists are interested in all sorts of questions, including "what is the best study break." Here's a study that tested how taking a short walk as a break from studying affected student's ability to memorize a series of numbers. It turns out that taking a walk in the woods significantly boosted student's memory compared to those who took a walk along city streets, or did not take a break at all.

What is the best way to take a study break?

Master the art of stealth studying

This is another great post from Study Hakcs on how to master the art of stealth studying.

Some tips:

1. Construct study guides on the fly.
   When taking notes — in class or while doing a reading assignment — start constructing your study guide at the same time. The easiest way to do this is to copy the questions from your question/evidence/conclusion clusters and paste them at the top of your document as you go along.
   Print study guides immediately after construction.
   This is a great way to do FARMIPS—simply write out a question during our discussion and save it for later
   
   
2. Print study guides immediately after construction.


As the professor winds down, or as you finish your reading assignment, send your notes to the nearest public printer. (Or e-mail them to yourself so you can load it up on a public computer connected to a printer). Before doing so, however, reduce the font to the smallest size you can still read. (This will prove useful later.) As you walk out of the classroom, or library, swing by the printer to grab your printout.
Review using the “10-Minute Detour” method.

As soon as you have your first study guide printed, start looking for ways to add a 10-minute detour to a walk across campus you already need to do. Make these detours pass through somewhere quiet and unpopulated. During these detours take out one of your expanded study guides and start doing a quick quiz-and-recall review. Do this out loud. As you walk. (It’s okay to do this quietly to prevent unexpected institutionalization). In 10 minutes you might knock off 2-4 questions. Some additional notes on this process:



• Get in the habit of sprinkling these detours throughout your working hours on working days. (If you’re between classes, your mind is probably already in a deep thinking mode — or a mild coma, depending on the professor).



• Try to review new material within 24-hours to help cement it while it’s still fresh.





3. Ask questions every class. Attend every office hours.

To make stealth studying work, you need to understand all the material as quickly as possible. This means you need to come to class attentive and be a question-asking fiend. When you don’t quite understand how something fits a broader point, ask. If you don’t want to keep interrupting the class, save a collection of specific, concise questions to ask the professor immediately following class. Attend office hours most weeks to discuss the topics you found most difficult. Think of this as a pain-free, advanced review session. We have no time to spare for you to re-learn this material later on before the test. If you don’t get it down the first time, we can’t get your study time down to an hour.

The physics of free throw shooting

Now that basketball season is here, it's a good thing that physicists have worked out the best way to shoot a free throw.

See here: The physics of free throw shooting

Some tips from the article:

First, the engineers say that shooters should launch the shot with about three hertz of back spin. That translates to the ball making three complete backspinning revolutions before reaching the hoop. Back spin deadens the ball when it bounces off the rim or backboard, the engineers assert, giving the ball a better chance of settling through the net.
Where to aim? Tran and Silverberg say you should aim for the back of the rim, leaving close to 5 centimeters - about 2 inches - between the ball and the back of the rim. According to the simulations, aiming for the center of the basket decreases the probabilities of a successful shot by almost 3 percent.

The engineers say that the ball should be launched at 52 degrees to the horizontal. If you don’t have a protractor in your jersey, that means that the shot should, at the highest point in its arc to the basket, be less than 2 inches below the top of the backboard.
Free-throw shooters should also release the ball as high above the ground as possible, without adversely affecting the consistency of the shot; release the ball so it follows the imaginary line joining the player and the basket; and release the ball with a smooth body motion to get a consistent release speed.

“Our recommendations might make even the worst free-throw shooters - you know who you are, Shaquille O’Neal and Ben Wallace - break 60 percent from the free-throw line,” Silverberg says with tongue firmly in cheek. “A little bit of physics and a lot of practice can make everyone a better shooter from the free-throw line.”