Newton's Second Law for Rotation

Remember Newton's Second Law? Turns out there's an equivalent for rotational motion!

Notes: Torque and Angular Acceleration

Remember that your mobile is due Tuesday, but you can bring it in anytime before that as well.

Tonight's homework:

Rotational Motion TIPERs #5 (started in class)
Ch, 8 (p. 269) #31 & 32

Mobile Work Day

Today is your only in-class time to work on the Mobile Project. This is due Next Tuesday after the Martin Luther King, Jr. day weekend.

Here are some instructions that ended up on the board:







If you use standard units for everything, you should get a net torque of less than 0.001 N-m for each level. If you get something larger than that, you need to justify it by explaining errors that occured and how they would have affected your net torque calculations.

You do not have any additional homework tonight.

Torque and Equilibrium

Today we talked about the conditions necessary for equilibrium. That is:

Net force = 0
Net torque = 0

We did a problem together and Rotational TIPERs #4.

Homework is Ch.8 (p. 265) #8 & 21

We also passed out the instructions for our Mobile Project, which will be due on January 19th. You will have the next class period to work on this, but no other class time.

Torque

We spent the first part of class going over your labs from yesterday, then used your ideas from that lab to come up with the equation for torque. The notes ended up on the board, not in a Powerpoint:




We then worked on Rotational Motion TIPERs #2 and Rotational Motion TIPERs #3 (email miss.volkening@gmail.com for copies).

Homework is Chapter 8 (p. 264) #2 & 3

Note: if you were absent and unable to present today, I need to check your lab in your lab notebook.

Torque Lab

Today we completed a short lab:

Torque Lab

Your homework is to finish up your graph and explanation about the slope and y-intercept. Tomorrow your group will briefly present your results.

Center of Mass

Welcome back! Today we talked about the center of mass: what it is, how to find it, and some cool things we can do with it.

Notes: Center of Mass

We also completed this short qualitative lab:

Choose at least 3 different cardboard pieces. Sketch them in your lab notebook and qualitatively find their centers of mass. Write a brief description of your procedure and mark the COM on your sketches in your notebook.

Your book does not have many problems involving only the center of mass, so I had to make up a problem. Your homework is:

1.A uniform meter stick has a mass of 0.20kg.

a)Where is its center of mass?

b)A 0.30 kg mass is taped to the meter stick at the 80 cm mark. Now where is the COM of the system?

+Ch.8 (p. 272) # 69

Also, a few of you asked for the address of the planets simulation some classes looked at:
My Solar System

Final Practice

We don't have enough time for a unit test on momentum, so instead your final will consist of multiple choice problems from the whole semester and free response problems only from the momentum unit.

Here is the practice test for the free response section of the final. The best way to study for the multiple choice section is to review the multiple choice problems from previous tests and practice tests.

Here are the video solutions for the free response practice problems:

#1
#2
#3
#4