Differential moment of inertia

In summary, differential moment of inertia is a measure of an object's resistance to changes in its rotational motion, taking into account the distribution of mass and distance from the axis of rotation. It is calculated using the formula I = ∫r²dm, and is different from the general term moment of inertia, which refers to an object's resistance to changes in rotational motion in general. A higher differential moment of inertia means more resistance to changes in rotational speed, requiring more torque to accelerate or decelerate. Additionally, differential moment of inertia cannot be negative as it is a measure of resistance and must always be a positive value.
  • #1
kyu
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Homework Statement



since it's asking us to find the moment of inertia with respect to y-axis, why did they draw the differential element to x-axis?

Homework Equations





The Attempt at a Solution



because of the initial problem.. i don't know how to start.. so

dA = x dy
I(y) = x^2 (x dy)
 

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  • #2
since it's asking us to find the moment of inertia with respect to y-axis, why did they draw the differential element to x-axis?
... they show an element width dy and length x at position y=x^3.
How would you do it?
 

FAQ: Differential moment of inertia

1. What is differential moment of inertia?

Differential moment of inertia, also known as rotational inertia, is a measure of an object's resistance to changes in its rotational motion. It takes into account the distribution of mass in an object and the distance of each mass from the axis of rotation.

2. How is differential moment of inertia calculated?

The formula for differential moment of inertia is I = ∫r²dm, where I is the moment of inertia, r is the distance of a small mass element from the axis of rotation, and dm is the mass of the small element. This integral is typically done over the entire object to find the total moment of inertia.

3. What is the difference between moment of inertia and differential moment of inertia?

Moment of inertia is a general term that refers to an object's resistance to changes in rotational motion. Differential moment of inertia specifically refers to the change in moment of inertia with respect to a small change in angular velocity.

4. How does differential moment of inertia affect an object's rotational motion?

The higher the differential moment of inertia of an object, the more resistance it has to changes in its rotational speed. This means that it will require more torque to accelerate or decelerate the object's rotation.

5. Can differential moment of inertia be negative?

No, differential moment of inertia cannot be negative. It is a measure of an object's resistance to changes in rotational motion, so it must always be a positive value. A negative value would imply that the object would accelerate in the opposite direction of the applied torque, which is not physically possible.

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