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

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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.