Total Kinetic Energy in a System

AI Thread Summary
The discussion focuses on calculating the total kinetic energy of a system using the total moment of inertia. The user initially computes the x and y components of inertia for two particles, resulting in 11mr^2 for the total y component. They attempt to apply the kinetic energy formula K = 1/2mv^2 but struggle with the correct application of the components. After some confusion, they realize that only the y-components should be used for the calculation. The final kinetic energy expression is clarified to be based solely on the y-components.
Todd88
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Homework Statement


Using the total moment of inertia of the system, find the total kinetic energy of the system.

Here is the diagram:

134726A.jpg



Homework Equations


Find the total kinetic energy of the system using m, r, w.


The Attempt at a Solution



For particle a, I found the x and y components of inertia to be mr^2 and 9mr^2 respectively. I found the total y component of inertia of the system to be 11mr^2. I can't seem to find the total kinetic energy. I thought that if you take the original equation:

K = 1/2mv^2 and plug in the components => K = 1/2m(r^2+9r^2) = 5mr^2 for particle A

K = 1/2mv^2 and plug in the components => K = 1/2m(r^2+16r^2) = 17/2mr^2 for particle B

Then add the two quantities to get 27/2mr^2w^2 for the kinetic energy. This isn't right...anything to help me would be much appreciated! Thanks!
 
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...nvm I am only suppose to use the y-components for some reason. Thanks.
 
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