How Fast Does the Rim of a Rotating Disk Move?

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The discussion centers on calculating the speed of a point on the rim of a rotating disk with a given mass and diameter. The kinetic energy formula used is 1/2mv^2, leading to a calculated speed of 1.73 m/s. However, the conversation highlights the need to use the rotational kinetic energy formula instead, which is more appropriate for this scenario. Participants emphasize understanding the relationship between angular velocity and linear speed. The importance of using the correct formulas for rotational motion is clearly underscored.
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Homework Statement



A thin, 100.0 g disk with a diameter of 8.00 cm rotates about an axis through its center with 0.150 J of kinetic energy.

What is the speed of a point on the rim?


The Attempt at a Solution



1/2mv^2 = 0.15
v = 1.73m/s

I know
Vt = angular velocity x r

I am not sure how to solve foe the angular velocity
 
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1/2 mv^2 = kinetic energy, correct. However, here you're dealing with rotational KE. You need a different formula. Does that help?
 

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