What Happens When an Object with Zero Rotational Inertia Spins?

AI Thread Summary
The discussion centers on the concept of an object with zero rotational inertia and the implications of such a scenario. Participants argue that an object cannot exist without inertia, as inertia is inherently linked to mass. The idea of a point mass lacking rotational inertia is debated, with emphasis on the challenges of defining the spinning of a dimensionless point. The conversation highlights the confusion surrounding hypothetical situations that contradict established physics principles. Ultimately, the concept of spinning without inertia is deemed not physically meaningful.
Mt. Nixion
Messages
47
Reaction score
1
Let's say that something is spinning and it spins in a certian direction. The object has rotational inertia. Now say that the object has no inertia. How many times will the object change its direction of rotation in under a second?
 
Physics news on Phys.org
I am not understsnding yous question.whenever there is mass there is inertia.I think you can't think of object without inertia.
 
A point mass would have no rotational inertia. However, spinning of a point is not very well defined.
 
Mt. Nixion said:
Let's say that something is spinning and it spins in a certian direction. The object has rotational inertia. Now say that the object has no inertia. How many times will the object change its direction of rotation in under a second?
I don't understand the point of this (and most of the questions you've posted here). They usually start with a half-described situtation, then you ask what amounts to "what would happen if what we know about physics (or reality) wasn't true?". It's hard to tell if you are serious or just goofing around; if serious, what kind of answer are you expecting?

In this particular case, assuming the object has no inertia is not physically meaningful.
 
DavidK said:
A point mass would have no rotational inertia. However, spinning of a point is not very well defined.
How can the spinning of a point which has no dimension be defined.
 
vaishakh said:
How can the spinning of a point which has no dimension be defined.

It is not.

DavidK said:
However, spinning of a point is not very well defined.
 

Thread '1:1 versus 2:1 Mechanical Advantage debate'

The rope is tied into the person (the load of 200 pounds) and the rope goes up from the person to a fixed pulley and back down to his hands. He hauls the rope to suspend himself in the air. What is the mechanical advantage of the system? The person will indeed only have to lift half of his body weight (roughly 100 pounds) because he now lessened the load by that same amount. This APPEARS to be a 2:1 because he can hold himself with half the force, but my question is: is that mechanical...
View full post »

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 'Newton's first law?'

Some physics textbook writer told me that Newton's first law applies only on bodies that feel no interactions at all. He said that if a body is on rest or moves in constant velocity, there is no external force acting on it. But I have heard another form of the law that says the net force acting on a body must be zero. This means there is interactions involved after all. So which one is correct?
View full post »

Similar threads

I Counter-rotating mass to counteract inertial spin
Replies
10
Views
2K
Why Do Different Objects Share Similar Moments of Inertia?
Replies
1
Views
2K
B The physics of flywheel launchers (like tennis ball shooters)
2
Replies
60
Views
4K
Spinning objects and angular acceleration
Replies
1
Views
1K
Does mass distribution affect an object's ease of rotation?
Replies
13
Views
2K
I Energy of spinning objects as axis of rotation moves
Replies
1
Views
1K
How can I calculate the moment of inertia of any object?
Replies
10
Views
2K
About gymnastic spins (moment of inertia related)
Replies
15
Views
3K
The conservation of angular momentum
Replies
9
Views
5K
Classical Rotation: Referencing Rotational Motion in Mechanics
Replies
5
Views
1K

Hot Threads

Recent Insights

Back
Top