Today,we'll break into groups tosolve center of mass problemsfrom Chapter 9:

Required: 59, 61, 62, 64, 65 Enrichment: 66, 67

These problems will require you to use the calculus and what you learned about different kinds of densities. You may want to look at the following videos for reference: The first video shows you the theory on finding the center of mass. The second video shows you how to find the center of mass of an object using the summation. The third and fourth videos show you how to use the integral to find the center of mass.

Center of Mass Theory (vkiledj)

Center of Mass with Summation (vkiledj)

Center of mass with integral, part 1 (vkiledj)

Center of mass with integral, part 2 (vkiledj)

Homework: Sorry - traditional homework tonight. Finish all required problems you did not get to in class. It is very important that you do these required problems. Also, make sure that you're comfortable with Example 9-14 on page 223 of your textbook. Try recreate the solution the problem from the 3rd and 4th video from last night independently. That means to write out your own solution without watching the video. The problem is to find the center of mass of a non-uniform rod length L where λ = kx^{3}. If you get stuck, rewatch the videos: