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 Page 2
This text is meant to accompany class discussions. It is not everything there is to know about the basics of torque and the two conditions of equilibrium. It is meant as a prep for class. More detailed notes and examples are given in the class notes, presentations, and demonstrations (click here.)

Example 3 Finding the Center of Mass Using Torque

This 3 minute video describe how to use torque to calculate the location of the center of mass/center of gravity and the importance of the center of mass to the weight.

This YouTube video is here: http://youtu.be/OwIphm_vKOc

Let's take this one step further.

If this is expanded, the equation for finding the center of gravity or center of mass looks like this.

This can be expanded further by replacing "w" with "mg."

The g's divide out. This only works because near the surface of the Earth, the acceleration due to gravity is fairly constant. So every value for "g" is the same. Once you eliminate the acceleration due to gravity, The formula now stands for finding the center of mass and looks like the formula below.

In "geek-speak" this looks like the formula below.

Remember, because the acceleration due to gravity is so consistent near the surface of the Earth, that the center of mass and center of gravity are at the same locations on a body. That makes this formula a great shortcut for finding the center of gravity as well as the center of mass.

 Example: Center of Mass/Center of Gravity Question Video Solution Solution While sitting in a marketing meeting for new add campaign to show of a balanced diet, Derbel McDillet came up with an idea to emphasize a balanced diet. He thought to start by balancing fruit and bread on a board. You job, as the intern, is to figure out where to hold up the board. This YouTube videocan be found at http://youtu.be/S2wPQOzk3rM

by Tony Wayne ...(If you are a teacher, please feel free to use these resources in your teaching.)