Sphere vs Cube: Rotational Inertia

AI Thread Summary
A sphere has less rotational inertia compared to a cube when both have the same mass and the cube's side length equals the sphere's diameter. The rotational inertia of a solid sphere about its center is calculated as (2/5)mr², while the cube's inertia is (1/6)ml² for rotation about an axis through its center. Given the dimensions specified, the cube's larger moment of inertia results from its shape and distribution of mass. The discussion emphasizes the importance of understanding the theory behind moment of inertia calculations. Overall, the cube exhibits greater rotational inertia than the sphere under the given conditions.
PhysicsKid0123
Messages
95
Reaction score
1
Which would have more rotational inertia? A sphere or cube?
Suppose they have the same mass, the side of the cube has the same length as the diameter of the sphere, the cube's rotation axis is perpendicular to two of its faces. Which one would have more rotational inertia about an axis through the center of mass?
 
Physics news on Phys.org
Ya know, you can look this stuff up.
 
What about the explanation/theory?
 

Thread 'Is calling fictitious forces "not real" just about terminology?'

Hi there, im studying nanoscience at the university in Basel. Today I looked at the topic of intertial and non-inertial reference frames and the existence of fictitious forces. I understand that you call forces real in physics if they appear in interplay. Meaning that a force is real when there is the "actio" partner to the "reactio" partner. If this condition is not satisfied the force is not real. I also understand that if you specifically look at non-inertial reference frames you can...
View full post »

Thread 'Derivation of Hamilton's Principle: Questions'

I have recently been really interested in the derivation of Hamiltons Principle. On my research I found that with the term ##m \cdot \frac{d}{dt} (\frac{dr}{dt} \cdot \delta r) = 0## (1) one may derivate ##\delta \int (T - V) dt = 0## (2). The derivation itself I understood quiet good, but what I don't understand is where the equation (1) came from, because in my research it was just given and not derived from anywhere. Does anybody know where (1) comes from or why from it the...
View full post »

Similar threads

I Explanation of parallel axis theorem
Replies
2
Views
1K
I Inertia of body moving about two distinct parallel axes
Replies
10
Views
2K
I Effects of External Torques on the Angular Momentum of Asymmetric Bodies
Replies
3
Views
2K
B Moment of Inertia of Rectangles
Replies
3
Views
3K
Why Do Different Objects Share Similar Moments of Inertia?
Replies
1
Views
2K
I Moment of inertia of human body with limbs at an angle
Replies
12
Views
2K
How can I calculate the moment of inertia of any object?
Replies
10
Views
2K
Toy Problem to Understand Products of Inertia?
Replies
3
Views
2K
I A rod that falls while rotating from the end of a table
Replies
2
Views
1K
B Sympathetic motion generated by cleaning Rubik's cube
Replies
10
Views
501

Hot Threads

Recent Insights

Back
Top