Is a Rigid Body Always Concentrated at its Center of Mass in Circular Motion?

AI Thread Summary
In circular motion, a rigid body can often be treated as concentrated at its center of mass for analyzing translational motion, allowing the use of Newton's second law, ΣF = ma_cm. However, this simplification does not apply universally, especially when considering rotational dynamics, such as moment of inertia. The distinction between translational and rotational motion is crucial, as forces acting on the body may not solely influence its center of mass. A mathematical proof or specific examples are needed to clarify when this assumption holds true. Understanding these principles is essential for accurate analysis in physics.
atavistic
Messages
105
Reaction score
0
When considering pure rotation of a rigid body about some point , then can we always consider the body to be concentrated in its centre of mass and use all force related equation treating it like a point object situated at it center of mass.? Why? Can anyone prove mathematically because there are many things like moment of inertia ,for e.g, for which we cannot do that.
 
Physics news on Phys.org
BUMP please I really need this in a few hours.
 
I'm not sure I understand your question. If you're asking whether Newton's 2nd law for translation applies--sure:

\Sigma F = ma_{cm}

If that's not what you mean, please give a specific example of your concern.
 

Thread 'Average velocity as a weighted mean'

Hello everyone, Consider the problem in which a car is told to travel at 30 km/h for L kilometers and then at 60 km/h for another L kilometers. Next, you are asked to determine the average speed. My question is: although we know that the average speed in this case is the harmonic mean of the two speeds, is it also possible to state that the average speed over this 2L-kilometer stretch can be obtained as a weighted average of the two speeds? Best regards, DaTario
View full post »

Thread 'Inclined treadmills and Galilean Invariance'

This has been discussed many times on PF, and will likely come up again, so the video might come handy. Previous threads: https://www.physicsforums.com/threads/is-a-treadmill-incline-just-a-marketing-gimmick.937725/ https://www.physicsforums.com/threads/work-done-running-on-an-inclined-treadmill.927825/ https://www.physicsforums.com/threads/how-do-we-calculate-the-energy-we-used-to-do-something.1052162/
View full post »

Similar threads

I The proportion of kinetic energy of a rotating rigid body?
Replies
7
Views
1K
I Why does a free rigid body rotate only about its COM when F(ext) is applied?
Replies
7
Views
2K
A Rigid body motion (RBM) transformation
Replies
3
Views
1K
Projectile motion of a two-point rigid body
Replies
8
Views
2K
Rigid body mechanics, solution seems incorrect?
Replies
1
Views
3K
Rigid body kinematic motion and rotation
Replies
13
Views
2K
Rotation of a rigid body about external axis
Replies
10
Views
3K
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
Rigid body with center of rotation other than CoM
Replies
15
Views
3K

Hot Threads

Recent Insights

Back
Top