Moment of Inertia and Angular Velocity

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Homework Help Overview

The discussion revolves around a problem involving moment of inertia and angular velocity, specifically in the context of a student holding a textbook while spinning. The scenario includes parameters such as mass, angular velocity, and distance from the axis of rotation.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • Participants discuss the relationship between angular momentum and moment of inertia, with some questioning how to determine the initial moment of inertia without knowing the radius. Others suggest using conservation principles.

Discussion Status

Some guidance has been offered regarding the conservation of angular momentum, and there appears to be an ongoing exploration of the problem. One participant expresses confusion about the approach but later indicates they have resolved their issue.

Contextual Notes

There is mention of missing information regarding the radius in relation to the moment of inertia, which is a point of confusion for participants. The discussion reflects the constraints of the homework context.

primeboss
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Homework Statement


A student hold a 2.0 kg textbook to their chest as they spin at an angular velocity of 6 rad/sec. Assuming the mass moment of inertia of the student to be 1.4 kgm^2, what is the angular velocity if the student hold the book 0.7 meters away

Homework Equations


The Attempt at a Solution


I do not know where to start. i can find a correlation with angular velocity and moment of inertia. Also do i use energy?
 
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welcome to pf!

hi primeboss! welcome to pf! :smile:

momentum and angular momentum are always conserved :wink:
 
Thanks for the reply, but i am still confused into how to approach the problem
 
uhh? :redface: use conservation of angular momentum …

what do you get?​
 
"I don't see how i can find the intial momentum of inertia, since i do not know the radius but only the mass"

edit:NEVERMIND i got it. Thanks for all your help.
 
Last edited:

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