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Moment of Inertia of Door

  • Thread starter JMUkid
  • Start date
  • #1
2
0

Homework Statement



A 32kg door that is 107 cm wide. What is the moment of inertia 10 cm inside the door with rotation around a vertical axis?

Homework Equations



L=Iω

The Attempt at a Solution



I=1/3mL^2
I= Icm+ md^2

1/3(32)(107)^2
Im not sure what to do after I find the I center of mass

Homework Statement





Homework Equations





The Attempt at a Solution

 

Answers and Replies

  • #2
134
0
Your question is confusing.Give more details.Whether the door is rotating in vertical plane or horizontal plane??
 
  • #3
2
0
It is rotating around a vertical axis
 
  • #4
134
0
It is rotating around a vertical axis
But in which plane???
I mean that whether the door is on floor and rotating about vertical axis or in an erect position rotating about vertical axis.Moment of inertia in both cases is different.
 
  • #5
390
1
It seems fair to assume from the question that the door is mounted to a vertical pole 10cm from its longest edge and parallel to that edge.
JMUkid you should try doing a search for the "parallel axis theorem" :)

EDIT: Looking at your working it looks like you've already got the formula there for your moment of inertia, you just need to add the second term in your second formula to your answer :)
 

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