SUPER CONFUSING linear algebra question

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Homework Help Overview

The discussion revolves around a linear algebra question involving angular velocity and cross products. The original poster expresses confusion regarding the steps in the provided solution, particularly about the meaning of omega and the operations performed with the vector (1,1,1).

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • The original poster attempts to understand the parametric equation of a vector and the subsequent steps in the solution, questioning the meaning of omega and the rationale behind specific mathematical operations. Some participants provide clarifications about angular velocity and suggest looking up definitions for better understanding.

Discussion Status

The discussion is ongoing, with participants exploring definitions and relationships in the context of the problem. Some guidance has been offered regarding the meaning of omega and the general relation between rotation axis and velocity, but no consensus has been reached on the original poster's specific questions.

Contextual Notes

The original poster references a picture that is not visible in the thread, which may limit the clarity of the problem context. There is also an indication of a step-by-step approach desired by the original poster.

theBEAST
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SUPER CONFUSING linear algebra question :)

Homework Statement


I have attached a picture of the question with a solution.

The Attempt at a Solution


Well... First i found the parametric equation of the vector L... Yeah...

So even looking at the solution I am confused. I get the conversion that they made to rad/s but the steps after that blow my mind :|. What does omega mean and also why did they multiply by (1,1,1) and then took the cross product of this point and the direction of the rod?

I want to get through this step by step.

Thank you!
 

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where's the pic ;)
 


susskind_leon said:
where's the pic ;)

Wow I was so excited I forgot about the picture LOOL
 


Lol
So, Omega means angular velocity (how many rads per unit time, in this case, minute). You should look it up on wikipedia, it reveals useful information for you.
Omega vector is the angular velocity times the unit vector of the rotation axis, which is (1,1,1)/sqrt(3)
Now, rotation axis cross position vector equals velocity is a general relation.
(If you don't believe me, look at a circularly rotating particle in the xy-plane, for example. Compute the velocity by taking d/dt r(vec). You will see, it holds. Now do the same in the xz- and yz-plane and argue that you can choose any plane.)
Now you only need to take the length of v and you're done.
 

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