A 10.7 g CD with a radius of 6.06 cm rotates with an angular speed of 30.9 rad/s. What is its kinetic energy?(adsbygoogle = window.adsbygoogle || []).push({});

What angular speed must the CD have if its kinetic energy is to be doubled?

Here is my work:

kinetic energy energy = 1/2 m v2

= 1/2 m ( r ω )2

= 0.5 x 0.0107 x ( 0.0606 x 30.9 )^2 J

angular speed must be increased by ( 2)^ 1/2 if kinetic energy is duobled

since kinetice enrgy is proportional to ω2

That answer isn't right, it comes out to be 0.188 J, can anyone tell me what is wrong with my equation?

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# Homework Help: Rotational Kinematics & Energy

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