Moment of Inertia Problem: Perpendicular Axes THM

Click For Summary
SUMMARY

The discussion centers on the application of the Perpendicular Axes Theorem (PAT) to determine the moment of inertia (MoI) of a thin, uniform square sheet with mass M and side length L. The correct moment of inertia through any axis in its plane is established as 1/2 M L^2, while the moment of inertia through the center of mass is 1/6 M L^2. The user initially miscalculated the moments of inertia, leading to confusion, but confirmed with a physics teacher that the correct calculation yields I_x = 1/12 M L^2 for axes in the plane.

PREREQUISITES
  • Understanding of the Perpendicular Axes Theorem (PAT)
  • Knowledge of moment of inertia calculations
  • Familiarity with uniform mass distribution in physics
  • Basic algebra for manipulating equations
NEXT STEPS
  • Study the derivation of the Perpendicular Axes Theorem in detail
  • Explore moment of inertia for various geometric shapes
  • Learn about the parallel axis theorem and its applications
  • Investigate the implications of mass distribution on moment of inertia
USEFUL FOR

Students studying physics, particularly those focusing on mechanics, as well as educators looking to clarify concepts related to moment of inertia and the Perpendicular Axes Theorem.

ultimateceej
Messages
6
Reaction score
0
[SOLVED] Moment of Inertia Problem: Perpendicular Axes THM

Homework Statement


First, the problem asked us to basically prove the Perp. Axes Thm and then use it to prove that the MoI of a thin, uniform square sheet with mass M and side L through ANY axis in its plane is equal to 1/2 M L^2



Homework Equations


The moment of inertia for a square sheet of a perpendicular axis through its center of mass is 1/6 M L^2


The Attempt at a Solution



First, I tried to simply say that I_x is perp. to I_y and that their sum is I_o which is equal to 1/6 M L^2 (above). And since the square is uniform, I_x = I_y = 1/2 I_o but this gave me I_x = 1/12 M L^2. Is it possible that the book has a misprint? How is it possible for the moments of inertia of an axis in the plane to be 3 times the MoI through the center of mass?
 
Physics news on Phys.org
Nevermind, physics teacher confirms the the typo. The correct answer is what I got, I_x = 1/12 M L^2
 

Similar threads

  • · Replies 1 ·
Replies
1
Views
2K
Replies
11
Views
4K
  • · Replies 21 ·
Replies
21
Views
3K
Replies
25
Views
2K
Replies
2
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 28 ·
Replies
28
Views
2K
Replies
3
Views
2K
  • · Replies 13 ·
Replies
13
Views
3K
Replies
52
Views
5K