Subtracting object MOI from assembly to get other parts MOI?

AI Thread Summary
To determine the moment of inertia (MOI) of a specific section of an assembly, such as the tail of an airplane, one cannot simply subtract the MOIs of known sections from the total MOI. The MOI depends on the distribution of mass relative to the axis of rotation, which means adjustments must be made for the position of each section. To find the unknown section's MOI, one must use the parallel axis theorem or other methods that account for the geometry and mass distribution. The discussion emphasizes the importance of understanding these principles for future applications in exams and real-world scenarios. A clear grasp of the underlying physics is essential for accurate calculations.
Jweck002
Messages
7
Reaction score
0

Homework Statement


It's been ages since I have done Moments of Inertia of complex objects! :( Can anyone help??
Say you have an assembly like an airplane and you want to just get the moment of inertia(MOI) of the tail section and you are given the Mass of whole plane,mass of tail section, moment of inertia of front section, and moment of whole plane(moments about each axis for both). Can you just subtract the MOIs of known sections to get the MOI of unknown sections? If not, how would you go about getting the unknown sections MOI from that info.

Homework Equations

The Attempt at a Solution

 
Physics news on Phys.org
You must show us your attempt at the solution before we are allowed to help.
 
Last edited:
Oh. Sorry I posted this question in wrong area. I don’t have a specific problem but wanted to know for future problems on exams and real world applications.
 

Similar threads

Can You Subtract Moments of Inertia to Find the MOI of Unknown Sections?
Replies
1
Views
1K
Moment of inertia of a non uniform disc
Replies
9
Views
6K
Moment of Inertia of a Rod with Two Uniform Masses Attached
Replies
2
Views
25K
Moments of inertia using parallel axis theorem
Replies
2
Views
3K
Proving generality of moment of inertia
Replies
4
Views
2K
Moment of Inertia spreadsheet calculator
Replies
1
Views
9K
How can I calculate the moment of inertia of any object?
Replies
10
Views
2K
Mass moment of inertia of an airplane about its main gear
Replies
9
Views
5K
Determine the mass moment of inertia of the assembly
Replies
6
Views
8K
Complex Moment of Inertia Calculation
Replies
3
Views
6K

Hot Threads

Recent Insights

Back
Top