# Calculate Inertial Constant K I for Sphere + 4 Disks

• GreenSabbath
In summary, the conversation discusses the calculation of an inertial constant for a flywheel, using the formula I = kMr^2. The speaker asks if they can calculate their own inertial constant by adding weights to a sphere with 4 disks around it. They are advised to use the Parallel Axis theorem, which states that the moment of inertia of a body is equal to the sum of the moment of inertia of the body's center of mass and the product of its mass and the square of the distance between the two axes. The speaker then expresses confusion about the relationship between alpha (angular acceleration) and spin velocity.
GreenSabbath
I = kMr 2
Where M is the mass of the flywheel, r its radius and k is its inertial constant.
Can I calculate my own inertial constant( a sphere + 4 disks around the sphere)

Thanks Help will be appreciated

So in short I am adding weight on the side of the ball .. as mass of the wieights is increased concentration of mass is distributed more... so I decreases. I am confused I don't understand the parallel axis theorm. An an increase in alpha would obviously mean an increase in spin velocity? Yes?

## What is the formula for calculating the inertial constant KI for a sphere and 4 disks?

The formula for calculating the inertial constant KI for a sphere and 4 disks is: KI = (2/5)mR2 + (4/5)md2, where m is the mass of the sphere and d is the distance from the center of the sphere to the center of each disk.

## What are the units for the inertial constant KI?

The units for the inertial constant KI are kgm2.

## How does the number of disks affect the value of the inertial constant KI?

The number of disks does not affect the value of the inertial constant KI. The value of KI is only dependent on the mass and distance of the sphere and disks.

## What is the significance of calculating the inertial constant KI for a sphere and 4 disks?

The inertial constant KI is a measure of the rotational inertia of an object. It is used in calculations related to the rotational motion of the sphere and disks, such as calculating the angular acceleration or torque.

## Can the formula for calculating the inertial constant KI be used for other shapes and configurations of objects?

No, the formula for calculating the inertial constant KI is specifically for a sphere and 4 disks. Other shapes and configurations may have different formulas for calculating their inertial constants.

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