# Moment of Inertia for a circular platform system

• fatfatfat
In summary, the conversation is about finding the moment of inertia of a system consisting of a spinning circular platform with a student standing on it. The solution involves using the conservation of angular momentum law and treating the student as a point mass. The student is unsure about how to find the moment of inertia for a point mass, but is provided with a resource to help understand it.
fatfatfat
I need to know how to figure out the moment of inertia of a system that consists of a spinning circular platform with a student standing still on the platform.

I figure that it would just be the sum of the moments of intertia of the platform and the student. I can figure out the platform's moment of intertia easy enough, but I'm not sure how to figure out that of the student.

...

Or am I headed in the wrong direction?

Any help will be appreciated :)

Well, normally such problems involve the conservation of angular momentum law (hence, the addition is correct) and either the angular momentum of the guy is given or you just call it L' but you won't really need to know the exact value to solve the problem.

What exactly is the problem you are trying to solve ?

marlon

fatfatfat said:
I figure that it would just be the sum of the moments of intertia of the platform and the student.
Absolutely.

I can figure out the platform's moment of intertia easy enough, but I'm not sure how to figure out that of the student.
Treat the student as a point mass. What's the moment of inertia of a point mass about some axis?

Yeah, it is a question about the conservation of angular momentum haha... and yeah, I read a question that was almost the same as mine somewhere else on the forums and it talked about point mass, but I don't think our teacher has discussed that yet. I don't know how to find the moment of inertia for one, I don't think. Maybe I know it and I just can't think tonight! haha. I don't know.

Last edited by a moderator:
Thank you!

## What is moment of inertia for a circular platform system?

Moment of inertia for a circular platform system is a measure of its resistance to rotational motion. It is a property that describes how the mass is distributed around the axis of rotation.

## How is moment of inertia calculated for a circular platform system?

Moment of inertia can be calculated by using the formula I = mr^2, where I is the moment of inertia, m is the mass of the object, and r is the distance from the axis of rotation to the point of mass.

## What factors affect the moment of inertia for a circular platform system?

The moment of inertia for a circular platform system is affected by the mass and distribution of mass around the axis of rotation. The larger the mass and the further the mass is from the axis of rotation, the higher the moment of inertia will be.

## Why is moment of inertia important in physics?

Moment of inertia is an important concept in physics because it is used to calculate the rotational motion of objects. It is also used in many practical applications, such as designing vehicles and machines that rotate.

## How does moment of inertia differ from mass and weight?

Moment of inertia is a measure of an object's resistance to rotational motion, while mass is a measure of the amount of matter in an object and weight is a measure of the force of gravity on an object. Moment of inertia is dependent on the distribution of mass around an axis of rotation, while mass and weight are not.

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