Boo....my turn for the flu

Wednesday:  finish the third page from yesterday's handout.  Read the problems, draw a force diagram for each and label the forces you can.  I will look at these tomorrow

Start taking a look at http://your29point5cmdolllovesphysics.blogspot.com/ 

Tomorrow you can start testing.  If you have a car from home that your action figure can sit in, modify the seat belt and the bumper as needed for safety.  If you do not have a car from home, there are red cars you can use in the bottom cupboard behind where Josh and Nathan sit.  Remember, you will need a front AND a back bumper.  Make an action step list of things you will need to do and bring, and your groups must be 3 or less.

Monday Blues, where Powell's kids have the stomach flus

Take your quiz.   The first problem is particularly open, so if everyone at a table picks the exact same things,  I will wonder how synced your brain waves really are.

Finish the bridge reflection if you have not as homework for tonight.

TODAY

Review the forces on this page, paying particular attention to the Frictional Force.

Do these seven problems in your notebook.  I will ask you about them tomorrow, and if you have questions.  Most likely, you will, so don't skip these, ok?

Skim these four problems if you have time.

Constant Velocity vs. Changing Velocity in Forces

Fill in your data from the hill lab here


We have been looking at force diagrams for a while now.  Today we're going to look at a pretty realistic simulation to see how these work in applied situations.

Got to http://phet.colorado.edu/en/simulation/forces-1d and download the Java applet.

http://www.math-aids.com/images/graphing-coordinate-plane-4singles.png

1.  Apply a force until the filing cabinet moves and then push it to the house.   Sketch the Force graph with the Fapp, the Ffric, and the Fnet.   I like to hit the Pause button at the bottom and then replay to do this.

2.  Repeat with two different objects.  Note the differences by sketching both of these, with x-y labels, as well.

3.  Try to get the force net to zero for the filing cabinet while it is moving.  When you get done, take a look at the acceleration-time tab a) before the cabinet moves  b) when the cabinet starts moving   c) while the cabinet has a net zero force.

Answers to work

Personal Bridge Reflection (due Wednesday at the beginning of class)

Watch the video

Answer the following

1. How much did your bridge hold?
2. How much did it cost, and how did you minimize your costs?
3. What is the mass of your bridge (using a scale)?  Convert to kg.
4. Calculate the force weight of the bridge, and the force weight of the load applied.
5. Calulate a ratio to show me the strength of the bridge (load/bridge)
6. Using the member data sheet, which bridge member held the greatest load? How do you know?
7. Can a member experience both compression and tension? Explain.
8. IS your bridge model a good fit for the bridge you made in the program? Why or why not?
9. Draw a force diagram for your bridge when the truck is on the left-hand side of the structure.
10. How does friction matter in this project?
11. Explain why a truss bridge is more common than a cable-stayed bridge over small creeks.
12. What have you reinforced in this project about statics, force diagrams, angles, and vectors.

This entire sheet should be 1-2 pages long, hand-written or typed.  If you hand-write it, take a picture and upload to Google Drive.  Either way, share the docs with me at marciarpowellATgmailDOTcom

Bridge Reflection

Before you test your bridge out, please fill this

PRE_REFLECTION form out.

Test the bridge.   You will need to place it between two stools.   Place material on it, and start adding mass.  You may use 100 g or 500 g masses.

Keep track of:

____mass of bridge (kg)  Remember, 1000g = 1 kg

____mass added to the bridge (kg)   Remember to stay out of the way of the masses.  DO NOT stand under the bridge, or with your head below the bridge.

____weight of the bridge (N)   Weight on Earth = mass(kg) X a(gravity).  The acceleration of gravity on earth is about 10 m/s/s

____weight of the mass added to the bridge (N)

____ length of the bridge (cm)




Take a series of pictures of the bridge

a) before you start  (your group members should all be in this picture)
b) when it has 1 kg of mass on it
c) when it has 2 kg of mass on it
d) when it has 5 kg of mass on it.
e) when it starts to torsion
f) after a bridge collapse

Use these pictures to help you with the reflection, and email me your favorite 3.
Then, fill out the FINAL REFLECTION

Bridge Building

I am ill today.  Boooo

Your goal for the day is to build your bridge using a scale of 1 cm = 2 m

Upon reflection, glue guns will be faster than Elmer's glue; that said, do not make a glopping pile of goo for every joint.   The orange cards should be used for the girder.

Extra glue and straws should be in the credenza.  You may have to move the tables. to get closer to a plug in.  Popsicle sticks are under the coffee pot in the free box.

Glue gun glue gets very hot.  Have one person operate the glue gun and others use the bamboo skewer to move the pieces.


Forgot your stuff?  That's not so good.  Bridges MUST be ready at the beginning of the class Tuesday.


Here's a sneak peak of tomorrow's assignment:   http://www.physicsclassroom.com/Class/newtlaws/u2l2c.cfm