Angular momentum of a rotating disk

Click For Summary

Homework Help Overview

The discussion revolves around calculating the angular momentum of a rotating disk with a specified mass and diameter. The original poster presents their calculations and seeks confirmation of their approach.

Discussion Character

  • Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to use the formula L = Iw, calculating the moment of inertia and angular velocity. They express uncertainty about their results and seek validation.

Discussion Status

Some participants provide feedback on the calculations, specifically pointing out a potential error in unit conversion from centimeters to meters. The conversation reflects an exploration of the calculations and assumptions made by the original poster.

Contextual Notes

Participants discuss the importance of unit conversion in the context of the problem, highlighting a specific mistake in the radius used for the moment of inertia calculation.

aligass2004
Messages
236
Reaction score
0

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.
 
Physics news on Phys.org
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! :)
 

Similar threads

Replies
26
Views
2K
Replies
5
Views
2K
Replies
9
Views
3K
  • · Replies 45 ·
2
Replies
45
Views
4K
  • · Replies 1 ·
Replies
1
Views
2K
Replies
30
Views
4K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 10 ·
Replies
10
Views
5K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 13 ·
Replies
13
Views
3K