Why Is My Calculation of Angular Momentum Incorrect?

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SUMMARY

The calculation of angular momentum presented in the discussion is incorrect due to the use of the wrong formula for the moment of inertia. The correct moment of inertia for a thin disk is I = ½Mr², not I = mr². The user calculated angular momentum using L = mr²w, which led to an erroneous result. The correct calculation should incorporate the proper moment of inertia to yield accurate angular momentum values.

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  • Understanding of angular momentum and its formula
  • Knowledge of moment of inertia, specifically for thin disks
  • Familiarity with rotational dynamics
  • Basic proficiency in unit conversions, particularly RPM to radians per second
NEXT STEPS
  • Review the formula for moment of inertia for various shapes, focusing on thin disks
  • Learn about the relationship between angular velocity and angular momentum
  • Study examples of calculating angular momentum in different physical scenarios
  • Explore the implications of incorrect calculations in physics problems
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vorcil
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i seem to have got it wrong,


http://img10.imageshack.us/img10/2373/masteringphysics.jpg

my solving:

L=IW
I=mr^2

L=mr^2w

L=2.7kg* (0.03^2) * w

w= 2*pi * 600rpm /60 =62.83 rad/s

L=2.7*0.0009*62.83 =0.15

and i got it wrong? i was pretty sure it was right,

help please
 
Last edited by a moderator:
Physics news on Phys.org
Hi vorcil,

The moment of inertia of the disk is ½Mr².
 
What's the moment of inertia of a thin disk/cylinder about what is in your case the x-axis?
 

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