Moment of Inertia of Systems Video Lessons

Example

# Problem: A person sits on a freely spinning lab stool that has no friction in its axle. When this person extends her arms:A) Her moment of inertia increases and her angular speed decreasesB) Her moment of inertia decreases and her angular speed decreasesC) Her moment of inertia increases and her angular speed increasD) Her moment of inertia increases and her angular speed remains the sameE) Her moment of inertia increases and her angular speed increases

###### FREE Expert Solution

The moment of inertia is given by:

$\overline{){\mathbf{I}}{\mathbf{=}}{\mathbf{m}}{{\mathbf{r}}}^{{\mathbf{2}}}}$

As the person stretches her herms, the value of r increases.

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###### Problem Details

A person sits on a freely spinning lab stool that has no friction in its axle. When this person extends her arms:
A) Her moment of inertia increases and her angular speed decreases
B) Her moment of inertia decreases and her angular speed decreases
C) Her moment of inertia increases and her angular speed increas
D) Her moment of inertia increases and her angular speed remains the same
E) Her moment of inertia increases and her angular speed increases