Angular momentum of a rotating disk

AI Thread Summary
The discussion centers on calculating the angular momentum of a rotating disk with a mass of 1.2 kg and a diameter of 3.6 cm. The initial attempt used the formula L = Iw, but the user made a conversion error from centimeters to meters, leading to an incorrect moment of inertia calculation. After realizing the mistake, they corrected the radius to 0.018 m, which allowed for the accurate computation of angular momentum. The conversation highlights the importance of unit conversions in physics calculations. The thread concludes with a friendly sign-off, emphasizing the collaborative nature of problem-solving.
aligass2004
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Homework Statement



What is the angular momentum of the 1.2kg, 3.6cm diameter rotating disk in the figure below?

http://i241.photobucket.com/albums/ff4/alg5045/ex13-47.gif

Homework Equations





The Attempt at a Solution



I tried using L = Iw. w = 600 rev/min x (1 min/60s) x 2*pi radians = 62.832. Then I found I = 1/2 m(r^2) = .019. Then L = 1.194, but it wasn't right.
 
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convert cm to m. looks like you made a mistake in the conversion. 1.8cm = 0.018m
 
Last edited:
Grrrr...I thought I did. I did kinda. I did I = 1/2 (1.2) (.18^2)...instead of (.018). I got it.
 
aligass2004 said:
Grrrr...I thought I did. I did kinda. I did I = 1/2 (1.2) (.18^2)...instead of (.018). I got it.

cool. yeah, just noticed the 0.18. When I first posted, I thought you left it as cm... but then I realized that that didn't make sense with the L you'd gotten...

I'll catch u later aligass2004. got to sleep.
 
Night! :)
 

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