(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A thin, 50.0 g disk with a diameter of 8.00 cm rotates about an axis through its center with 0.190 J of kinetic energy. What is the speed of a point on the rim?

2. Relevant equations

[tex]C = \frac{1}{2}MR^2[/tex]

[tex]K_{rot}=\frac{1}{2}I\omega^2[/tex]

3. The attempt at a solution

Since the formula for kinetic rotational energy is [tex]K_{rot}=\frac{1}{2}I\omega^2[/tex], and the constant for the moment of inertia for a solid disk with the axis of rotation about it's diameter is [tex]C = \frac{1}{2}MR^2[/tex], I substituted the I in the second equation with the first equation, resulting in the following:

[tex]K_{rot}=\frac{1}{2}(\frac{1}{2}MR^2)\omega^2[/tex]

Substituting the values that I was supplied with in the problem statement, I came up with this equation:

[tex]0.190=\frac{1}{2}(\frac{1}{2}(0.05)(0.04)^2)\omega^2[/tex]

Solving for [tex]\omega[/tex], I ended up with [tex]\omega \approx \pm 97.5[/tex], which was determined to be incorrect.

Any help would be extremely appreciated.

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# Homework Help: Rotating Disk

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