Class: October 30, 2009

Today in class, we started off by breaking off into groups to write equations that expressed how to find centripetal acceleration or the factors that affect it. On the board, there was a triangle that represented an angle (theta), the hyptonuse (length of the rope the object was attached to), and the side opposite theta (the radius of a circle). There was also a free body diagram of Ft pointing northwest, a dotted line going straight up, an angle between those two lines represented by the same theta, and gravitational force pointing straight down.

The first question we had to answer was which way the net force would point: a little less than horizontally in the west direction.

Question 2 asked to draw a diagram of all of the forces acting on the object expressed in the free body diagram. Unfortunately, I do not know how to put my picture of it on the post so I cannot show it.

The next question was to find an expression for R by using the triangle. We knew that the sin of theta was equal to the R/L, so we also knew that R was equal to sin of theta multiplied by L.

Question 4 was to find an expression for the Fnet by using theta and Ft. We knew that sin theta would be equal to Fnet/ Ft if we looked at the free body diagram, so we also knew that sin theta multiplied by Ft was equal to Fnet.

Question 5: Write an expression for Fnet in terms of m and ac. We knew that f=ma, so we also knew that Fnet=mxac. We also knew that ac=4 times pi squared/ t squared, so Fnet=m times ((4 times pi squared)/t squared))

Question 6: Use the expressions from 3, 4, and 5 to make an xpression for Ft. Ft= Fnet/sin theta. Using the previous equations, we knew Ft=(m(4 times pi squared times R/time squared)/(R/L). Simplified, Ft=(m(4 times pi squared/time squared)/L.

After that we went and saw the halloween parade, came back, and did the lab. Our homework is to plot a force vs. acceleration graph of our results.

This is the 100th scribe post. The next scribe is Jason. Happy Halloween.

Brian Cox on Stephen Colbert

This is great. Stephen Colbert takes on the LHC, and then he interviews Brian Cox, rockstar physcist.

The Colbert Report	Mon - Thurs 11:30pm / 10:30c
Big Bang Theory
www.colbertnation.com
Colbert Report Full Episodes Political Humor Religion

The Colbert Report	Mon - Thurs 11:30pm / 10:30c
Brian Cox
www.colbertnation.com
Colbert Report Full Episodes Political Humor Religion

10/28/09 Class

We spent the majority of class time today going over HW 4F and the concepts covered by said homework assignment. Problem 1a involves drawing a free body diagram for a 40 kg chest sitting on a 20° ramp with a man pulling on a rope attached to the chest at a 30° angle. The question asks you to solve for the minimum tension force the man must exert on the chest to keep the chest from moving (this problem disregards friction) using a graphical method. First you should solve for the only force you know at first: the gravitational force. Using the equation

, you can calculate the downward gravitational force to be about 400 N by calculating . Once you draw this into your FBD, you should be able to see

another fact; both the normal force and the tension force have to act in set directions. The normal force acts perpendicular to the surface while the tension force acts at 30° to the surface. Because the chest is not accelerating (or moving for that matter), the net force must be zero and when the vectors are drawn tip-to-tail when you add them up, they should form a loop. Therefore, you can draw lines along the points where the vectors should pass through (for example, the tension force vector must pass through the tail of the gravitational force vector). Once you have done this, you can see the length's of the normal and tension force vectors. Now you simply need to measure the length of the tension force vector and use your scale to find the approximate magnitude of the force (it should turn out to be about 150 N). The following shows what your finished vector drawing should look like:

For problem 1b, you are supposed to solve the problem using the component method. The three sets of components are , , and (these could be derived by using sin, cos, tan trigonometry). Knowing that the net force is zero, you can add up all the x-components and all the y-components and both sums will be zero. Knowing this and after solving the equations for the tension force, the tension force turns out to be about 158 N (very close to the graphically found answer from 1a).

This is what we did in class today. Next scribe is Jason.

Google Doc

Everything on the google doc has either already been revised or someone has dibs on it. Should I revise something again?

Ares 1-X launches

Ares 1-X, the most powerful rocket ever built since the Saturn V (which was used in Apollo) was launched today. This is the rocket that should be the future of the space program, and will take us to the moon and possibly Mars.



This is a great video, and there's enough information here to figure out some pretty interesting things. For one, what is the average acceleration of this rocket in m/s^2? (FYI- Mach 1 = 340 m/s = speed of sound)

Class tues Oct 27

Today in class we continued to work on centrifical acceleration. While going over our homework, we first established our formula to find centrifical acceleration (V^2/R) We then went in depth a little more by finding a different way to do this. We used this other formula (4piR/T^2) It is very important to remember when using these formulas that this only calculates the magnitude of the acceleration (the direction is always perpendicular to the velocity) We then started to explore components and go in to more depth with Ac by looking a rocket powered six flags ride that looked really fun. From a simple youtube video, we were able to find tension force, the force of gravity, and the total net force as well as the radius. After a long day of note taking, Mr. Burk decided to be gracious by doing a fun demonstration of "blood" separating due to the high amount of gravitational force on a spinney thing, as well as let us watch a bunch of people experience high gravitational force on the spinney carnival ride. The science behind both of these demonstrations are that the high gravitational force is essentially pushing the substance against the surface causing them to "stick" Finally, Mr Burk gave us all a 5 minute demonstration of the lab that we will do tomorrow (while nearly tacking off my head). For some reason, my computer wont let me ut up my pictures of notes and/or the board.

How to Upload a Graph to Google Docs

go to here for the video

graph_to_doc

October 26, 2009

Today in class we spent most of our time trying to understand the centripetal acceleration using examples drawn on the board. The first example was of a roller coaster that does a loop. at the right side of the loop the acceleration is pointing south west, at the top it is pointed straight downwards, and at the left side it is pointed southeast.

After we looked at the centripetal motion of the roller coaster, we took the picture of a circle and took the velocity at four points on the circle. The first figure represents the velocity vectors of each point taken on the circle, and the second figure shows the acceleration of each of the vectors. The acceleration of vector 1 goes down to the left because when the components of normal force pushing to the left and gravitational force are combined, the result is a southwest pointing vector which is the acceleration.

After we finished looking over centripetal acceleration, we used variables to convert what we already know about centripetal acceleration into an equation to find acceleration. The final equation to find acceleration comes out to be V^2/R , where v is velocity of the object and R is the radius from the center of the circle to the object.

Hw: Re-do Hw 3e with the notes we took today

Next scribe is Dylan

I am really lost with problem two on homework 4E. I think that it will keep getting farther away but I don't really know what to do.

Homework 4E

What is the question asking in Question 2 of 4E?

Want to see scribes at other schools?

We aren't the only class in the world with a blog and scribes who post summaries of the day's class. Take a look at these, and you might find some good ideas:

Scribes at other classes

Centripetal Force?

I know I'll probably get it eventually, but i'm having trouble understanding what the centripetal force is. I kind of imagine the pennies in the mall but I don't really understand, everything from the equations, to the actual concept, or the diagram on 3e. Can someone help me out? First off how do you calculate the centripetal force and what is the difference between the centripetal force and acceleration?

class on Wednesday the 21st

Today we started off by getting back a boatload of stuff. We got HW 4E-4H, two reassessments, and a couple of packets. One of these packets was the FARMIPS packet. This is where we can write a problem and a solution that is a concept on paper and show it to Mr. Burk. If we do 40+ of these on 10 different concepts, we will get 5 extra points on our exam - that would raise your avg. by 1 point. Also doing this will raise your experience with doing these types of problems, therefore getting you an A on the exam. But this will take time, you can't just do it the night before the exam - so start now. Next, we took notes on the lab we did yesterday. These notes were discussing how to use trig to find that Fnet on the object is 0.

opp/hyp=Fn/Fg=sinO, adj/hyp=Fn/Fg=cosO, so Ff= FgsinO=mg*sinO & Fn=mg*cosO when O= the angle of the ramp. MU=mg*sinO/mg*cosO = tanOmax.

(There is a picture above of this lab.)

The last part of class was dedicated to Tug of War. We split up into groups and discussed how Adam or Bob could win the contest. We realized that whoever exerted more Ff on the ground would win, because the Ftension on the rope from both sides are equal due to N3. we tested this out by putting 4 people, shoeless, one one side while the other 4 had shoes. With socks on, Ff is much less than with shoes on, so the shoe side owned because they exerted more Ff. Then later Jason almost got his shoulders dislocated. Homework is 4E and to give 30 mins. to the paper.

NExt scribe is Burge-asaUR.

Getting it wrong: surprising tips on how to learn

There's a GREAT article in scientific america talking about some of the latest research on how to learn.

When you have 15 free minutes you should ready this. (You probably have 15 minutes when driving to school, so why not download instapaper to your iphone, and read it on your phone).

Some highlights:

People remember things better, longer, if they are given very challenging tests on the material, tests at which they are bound to fail. In a series of experiments, they showed that if students make an unsuccessful attempt to retrieve information before receiving an answer, they remember the information better than in a control condition in which they simply study the information. Trying and failing to retrieve the answer is actually helpful to learning. It’s an idea that has obvious applications for education, but could be useful for anyone who is trying to learn new material of any kind.

By challenging ourselves to retrieve or generate answers we can improve our recall. Keep that in mind next time you turn to Google for an answer, and give yourself a little more time to come up with the answer on your own.

The article seems like it practically lifted my FARMIPS idea from today's class, but it talks about how you can adapt this method to any course—imagine making a super study guide for history, or English. How much could you rock those classes?

Google Docs

I don't know how to put my graphs up onto there either! If anyone would like to help or if anyone wants to tell me how to upload it that'd be great.

October 20th

Today we started off a reassessment. I'm not sure if I'm allowed to talk about it.....

Anyways, then we talked more about graphical vector constructions. Our goal was to be able to construct an acceleration vector at any point on the graph. The first thing we did was find the scale. Then, we found the change in position from one point to the next, and divided that by the change in time to get the change in velocity for that vector. Then, we repeated that with the next two points to find that velocity. We used those two velocities to find the acceleration at the point in the middle of the 3 points we used. To find the average velocity, we made a point in the middle of the first and second points given and drew a vector through the second point that was as long as the velocity we found earlier. We did the same for the next 2 points. Then, we connected the two vectors and made a resultant vector. This resultant vector is the velocity it takes to turn in a different direction and is also the direction of the acceleration. This kind of change in velocity is called centripetal. When the only thing that changes in velocity is speed it's called tangential. In the second period of today's double physics we did a lab that had to do with ramps and frictional force on blocks. We set the ramp at a 15 degree angle and calculated the frictional force by making a graphical vector.

That's all we did today during physics. Tomorrow's scribe is Gaston!

Paper

Hey I thought I had dibs on how mass affects friction (cough cough Gaston cough), but now that it's already written I can't really find anything more to write in the document.. Everything that was needed to be done was written already.... what do I do?

google docs issue

Google docs wasn't letting me copy and paste my graphs so I had to make a table... I am posting my graphs on the blog so anyone who would like to try to post my graphs can. Also, I only made one table because I have been attempting to paste my graphs for a very long time.

by the way if you miraculously can put my graphs up, you can just delete my table.

4d number 4

hey guys,

on question number 4 i am struggling on figuring it out... how is it possible to find the period without knowing anytimes or any other forces?

This could be you in 3 years

Want to see what other students, just like you can do if they put their minds to discovering something new in science, and work at it for 3 years?



Watch this. Oh, and if you were to win one of these awards, your worries about getting into a good college would be over. Colleges (all of them) would actively recruit YOU to come to their campus.

Here's the link to the description of this year's winners.

Why you should think about doing summer research in science

So you guys are through your first 9 weeks of physics, and now you have a better idea for why I showed you this picture on day 1.



Yes, this class is hard (but it should NOT feel painful, let me know if it does). Just like a great workout, you should have a sense of real accomplishment from this class. You should also know as your teacher, I'm often just like that spotter, pretty amazed that you're lifting all the weight you're lifting.

But my point is that now that you're getting a good workout, you should put your muscles to use. After all, lifting weights in the gym is fine and all, but the real fun is being bigger, faster or stronger in the sport you love.

In the world of science, science classes are the workouts (practice) and doing real research are the games. Believe it or not, you're ready to join a lab and do some real research starting tomorrow, and certainly by this summer, you could be part of a group of researchers who are doing cutting edge work on all sorts of amazing things.

Unlocking the secrets of the universe (especially when no one has discovered them before) can be immensely rewarding. Fame fortune and lots of prizes await you. But the most rewarding thing really is the fun you have from working in a lab with lots of cool people, playing with crazy toys, and discovering something no one has ever discovered before.

If you're interested in learning more about this, the time to start thinking about it is now. See me.

ps. Do click on the links above, they go to some cool stuff.

Paper

Hey everyone, can I claim the part about how mass affects the friction? Thanks! Oh, and I requested permission to edit the post but it's really late.... I don't know if it'll be accepted in time...

Hey guys. So I tried to get to the google doc. I logged in and everything, but I can't figure out how to edit it. And I started way too late...

paper

Hi guys. Can I get dibs on surface area? That it the topic I understand best.

Thanks, Dylan

Success requires hard work (but not all in one day)

This is a nice blog post that elaborates on many of the themes we've talked about before.

Success Requires Hard Work (But Not All in One Day)


Why not start writing a book?

While success may require a lot of hard work, that doesn’t necessarily mean that work is hard to do. A book may contain 80,000 words of carefully edited content, that’s a lot of hard work. But writing 800 words almost every day for four months isn’t hard to do.

Link to our paper

Here's the link to our paper

Factors that affect the frictional force on a sliding block.

October 19

Today in class we looked at a picture of an accelerometer and discussed the uses for it. I thought it was really interesting that they are used in the iphone to rotate the screen.
Then, we talked about the lab report that we are doing as a class. Tonight, everyone will write an entry that will help us come closer to finishing this project. We are including and introduction, apparatus, information about how mass, surface type, surface area, and velocity affect the blocks, modern studies, and a conclusion.

We went over our homework 4C. It involved adding and subtracting vectors.

For the last few minutes of class, we started graphical vector constructions. We found the change in position and the velocity from one point to the next. It is a better approximation if you find the change in position and velocity between the two points.

Homework for tonight is to write an entry for the lab report and homework 4D if you have time.
tomorrow's scribe is...Mary Elizabeth :)

If you liked the video on gravity...

You should check out the entire program called The Elegant Universe. You can watch all three hours online for free. It provides an explanation for string theory, which is a possible explanation for all the particles and forces in the universe, all being made up of tiny strings that exist in 10 dimensions. -

The website for the program is equally fantastic.

10/16/09

We started off class today by reviewing the concept of the two rooms. There are two sets of rooms, the first of which has one room in the middle of deep space and the other falling with the acceleration of g, or approximately 9.8 m/s^2. From the inside of these two rooms, there isn't an experiment that can be performed to distinguish the two. For example, if you release a ball in the air in either elevator, it will appear to stay in one place. In the deep space room, this is because it is truly weightless. For the falling room, this occurs because the ball accelerates downward at the same rate as the room and so appears to not move in relation to the room and everything in the room. The other set of rooms has one sitting on the surface of the Earth and the other in a deep-space rocket with an acceleration of 9.8 m/s^2. Einstein believed that these two rooms should be indistinguishable from the inside as well (for example, a ball dropped in the room on the Earth will accelerate downward at 9.8 m/s^2. The ball in the rocket room would attempt to keep a constant velocity due to its inertia but would appear to accelerate downward because the room is accelerating constantly so the floor is actually striking the ball. The ball drops on the surface of the Earth due to its gravitational mass while the ball in the rocket appears to fall due to its inertial mass). However, if he was to go by this theory, then light would need to behave the same in both rooms as well. A laser shined in the rocket room would attempt to move in a straight line, but since the room is accelerating constantly, it actually strikes a point on the wall slightly below where it would strike if the room had a constant velocity. Therefore, the laser would need to behave the same on the surface of the Earth, bending below a completly straight path. Because of this, Einstein believed that gravity must have some affect on light, a new idea for his time.

On a similar note, we also discussed the basics of Einstein's theory of general relativity. Before Einstein's time, Newton's theories regarding gravity were widely accepted; Newton stated that the force that makes things fall and the force that keeps things in orbit were one and the same, the force we know as gravity. However, not understanding how gravity worked, he more or less saw gravity as a mysterious force that large objects used to grab smaller objects (i.e. the Sun grabs the Earth and keeps it in orbit). However, Einstein proposed a new theory in the early 1900s and found a way to understand gravity. He thought of the first four dimensions as a single plane of "space-time fabric." Large, heavy objects, such as planets or stars would create dips in this space-time fabric which would alter the paths of things moving through the dip. Therefore, the force associated with gravity is really caused by objects being influenced by dips in the space-fabric. The following picture shows the Sun bending the space-time fabric and how this affects the surrounding planets:

As you can see in this picture, dips in the space-time fabric can not only change the paths of planets, but it can also influence the path of light. Today, this phenomenom is seen when we are able to observe stars that should be physically blocked by a large object, say the Sun. The following picture shows the light from a star bending around the Sun:

Point A in this picture is the actual position of the star. But because light bends around the Sun, we perceive the position of the star to be Point B, which would be the actual position of the star if the light was traveling in a straight line.

Finally, we also talked about frictional forces. Unlike normal forces which act perpendicular to a surface, frictional forces act parallel. However, these two kinds of forces are strongly related; the size of the frictional force depends on the size of the normal force (i.e. the harder you press two surfaces together, the greater the amount of frictional force). The general term "friction" can be divided into two different types of said force: static friction and kinetic friction. Static friction occurs when two surfaces have no relative motion, for example if a block is on a slanted surface but doesn't move. When surfaces have relative motion, kinetic friction occurs. You can see this when you slide a block along a tabletop. Friction is often quantified by using something called the "coefficient of friction." This is defined as the frictional force between two surfaces at any given moment divided by the normal force at that moment. The higher this number, the more frictional force for a smaller normal force (i.e. a big frictional force). After the friction talk, we split into groups and performed experiments to find the factors that affect or don't affect frictional force (we tested factors like mass, normal force, surface area, velocity, etc.).

These are the things we did in class today. Next scribe is Eliza.

what is this?

Propsicle to the first person to figure it out...

What's it like to win the nobel prize?

Carol Greider, winner of the 2009 Nobel prize for discovering discovering telomeres bits of seemingly useless DNA on the end of each of your chromosomes that progressively get shorter as you age and your cells reproduce. As it turns out, these bits of DNA are deeply linked to the aging process.

Anay, Dr. Greider has a fantastic interview with the NYT in today's paper, and one quote is absolutely worth reading and pondering.

Q. DID YOU ALWAYS WANT TO BE A BIOLOGIST?

A. My parents were scientists. But I wasn’t the sort of child who did science fairs. One of the things I was thinking about today is that as a kid I had dyslexia. I had a lot of trouble in school and was put into remedial classes. I thought that I was stupid.

I hope you'll take away the knowledge that if you struggle in science, or any subject, it is no measure of your ability to succeed in that field or your intelligence. Truly, hard work and persistence are the key to success at any level—even winning a Nobel prize.

Wenesday October 7

Today we started to work on the gravitational force lab. The lab is mostly about the gravitational force vector which on earth is 9.8N/kg.

class on 10-09-09! part 2

class on 10-09-09!

On Friday, we had a double period. It started off with getting the Reassessment 4 back. I guess i shouldn't talk about it, don't know if anyone still hasn't taken it. The Hw FOR friday was to finish the springs/Fg lab. It should be finished but we didn't go over it.

Instead, we started taking notes on the elastic force packet. We started by talking about how Hooke's law applies to our elastic force/spring stretch graph. The reason the line doesn't go through the origin is because when elastic force=0, the stretch of the spring is about 7 cm. Hooke's Law is that "Fs(change of x)=-k * (change of x)." The change of x is the stretch of the spring and k is the constant of proportionality. It's negative because change of x is opposite the Fs. Hooke's law is an empirical law because it is done by experiment, but it only works for us until the spring is stretched a certain distance, then the constant of proportionality changes.

Next, we talked about the FBDs of an upper book on a lower book. We put the forces in order of greatest to least to compare. Then we realized that force 1=force2=force3. This is because 1=3 (action/reaction - N2) and 1=2 (a=0,Fnet=o, Fg=-Fn - N3).

Then, we did an experiment with a mirror reflecting a laser beam. We put a heavy object on the table to see if the atoms in the table would compress and the light of the laser would rise. This actually did happen because the atoms of the table were compressed and became closer together because of the force exerted on it. With this, the bonds on the atoms pushed back even harder because of the reaction force.

Lastly, we took some notes and did a lab on Fg and Fn of a 700 N man standing on a scale in an elevator. In the notes, we said that when an elevator has a constant v, the scale will read 700 N. But when the elevator accelerates upward, the bottom of the elevator pushes on the man and he pushes back. So the reading > 700 N. But when the elevator is accelerating downward, the Fn on the man decreases. So the reading < 700 N. We put this into a real test when we all crammed into an elevator and saw Alexis's Fn increase and decrease as we did the respective tests.That's all on the day. HW: Web Assign Week Evaluation 8, homework 4B, and read Chapter 4:1-2. NEXT SCRIBE: it's Matthew, unless you've gone twice.

Question re: HW 4A

I do not understand 5c) and d) on homework 4A. For a) I got 2.4m therefore for b) I got 1.2m/s but then how do you find the instantaneous velocity when there is nothing past or before?

The nobel prize in physics

The Nobel prize in physics was just awarded today for the fundamental breakthroughs that led to two things you use just about every day. Fiber optics, the technology that allows light to carry gigabytes of information through optical fibers, allowing you to stream entire movies on your computer, or make a phone call to the other side of the world for pennies.

The other breakthrough was the development of the CCD, the charge coupled device, which you'll find in any camera phone, or digital camera. This discovery allowed us to convert tiny packets of light into electrical signals, which heralded digital photography. Once we started putting CCDs into telescopes like the Hubble, we could see incredibly feint objects billions of light years away, allowing us to peer at the universe as it existed billions of years ago.

NYT story on the physics nobel prizes


A great description of the discoveries from the Nobel Prize Committee

Tuesday October 6th Physics Class

In class today we started off by getting a few handouts. We got the chapter 4 reading, HW 4a, HW 4b, and a packet for the lab.

Next we expanded our knowledge of vectors. To subtract a vector A from a vector B, add the opposite of vector B. The opposite of a vector is just the same vector going in the opposite direction. You can also subtract vectors by putting them tail to tail.

http://mathforum.org/~klotz/Vectors/subtraction.html

We also found that to find -(vector A + vector B) you add the two vectors and take the opposite of the resultant.

After our discussion of vectors we started a new lab. Our first task was to find out how many Newtons are in one Spring Unit. After we did that we stretched an uncalibrated spring different amounts, measured the force, and graphed force vs. stretch of the spring (∆x). This lab is to be continued.

At the end of class we turned in the vector lab. Homework is 4a.

How do you make dry ice?

A number of you have asked questions about how to make dry ice. Ask the internet, and it delivers:

Monday

Today we took our assessment! I cannot talk about the assessment because some people haven't taken it yet. We also got back an overall concept sheet with our assessment grades and a sheet that will guide us through getting our averages. I was going to find a cool video about physics to put on the blog but I spent 30 minutes on youtube and I could only find this....

Our homework is the vector lab!

The next scribe is..... Sana!

http://www.youtube.com/watch?v=Y8skDy9Nn9I

I don't understand....

Hey everybodyy..

There are some things from the Unit 3 Major Concepts list that I don't quite understand and I'd like for you to help me out by explaining them?

3.4.4

Can you interpret graphs of acceleration vs force and acceleration vs 1/mass to find additional.... (it stops there)

3.5.1

Do you understand how the constant of proportionality, k, in N2 is determined by the units we.... (it stops there again)

3.6.1

Do you understand how to measure inertial mass?

3.7.2

Can you apply N3 to resolve the horse/cart paradox?

Thanks soo much!!

10/2/09 Class

The first thing we did in class on Friday, was to get back our 3E and 3F homework. We then talked about how the earth has a huge mass, which means it has a huge inertia. The moon and sun can change the velocity of the earth, it's always changing because we're orbiting. We exert force on the earth, because the earth exerts a gravitational force on us, but the force we exert is not enough to change the velocity of the earth. Footprints are proof that we put force on the ground. THe normal force of us on the earth equals the gravitational force of us on the earth, but if we are in quicksand there would be less normal force.
We went over many of the homework problems. The solutions are on the blog. Just dropped, a heavy dart and a light dart have the same acceleration. a=fnet/m, and if the darts were shot by a gun, the mass would be larger for the heavy dart. So it would have a larger acceleration. This happens because by the time the dart has left the gun, it already has a larger velocity.
When two vectors are added, the sum can be anything from zero to the sum of the lengths of the vectors. If you're confused about how to arranget the vectors, ask yourself "Is this something I could walk?"
The vector activity is due Tuesday. The vector activity sheet shows us how to do vectors on the calcuatlor, but be comfortable doing this with a ruler and protactor before you use the calculator. Our test is tomorrow. Study. Don't forget about the Unit 3 Review Sheet for practice.
The next scribe is Margaret

Want to know more about dark energy and dark matter? Check out this video.

Patricia Burchart, a particle physicist and professor at Stanford explains all we know about Dark Matter and Dark Energy. This is a great talk, in 16 minutes, it will explain our latest understandings about what our universe is made of.

September 30th Physics Class

Today we first turned in Homework 3F. At this point both 3E AND 3F should be turned into Mr. Burk. Then as class began, we reviewed vectors and scalars.
Some Examples of Vectors:

• Velocity
• Speed
• Acceleration
• Force
• Etc (Forces with Direction)
  

Some Examples of Scalars

• Quantities
• Time
• Position
• Temperature
• Etc (Forces without Direction)

Then we talked about how the earth is a giant magnet with a north and south pole just like a small magnet has a positive and negative end, and how a compass ( a magnet used for telling direction ) exerts a force on the earth but does not affect the earth greatly because it has a small mass. However the mass of the earth causes the magnet to spin around in the direction of north.

Then we finally proceeded to the last section of the Vector's lab, which involved going to the orange circle across from Campbell Hall, then we followed different bearings using the compass. Also as we followed the direction we timed the time it took to get there. We also measured how many meters one of our regular strides was. We then divided the number of meters per bearing by the number meters per stride to get the number of strides we needed to walk for each bearing.
They were as follows:
75m 30 degrees South of East
Go Down to the Path in front of the staircase infront of the bookstore.
50 m 35 degrees North of East
Down to the stairs infront of the Campbell Hall Parking Lot.
90 m 30 degrees North of West
Down across the Campbell Parking Lot to the path to PAWS seal.
50 m 50 degrees West of South
Down the pathway to the PAWS seal
75 m 30 degrees North of West
At this point using your compass you should be in front of Turner.
125 m 6 degrees West of South
Walk across down the path to the Turner carpool lane.
120 m 34 degrees North of East
Walk across Broyles Field to the Sculpture.
And that concludes the physics class. Next scribe is Mary Elizabeth.