Angular Momentum: Clarifying a Problem

AI Thread Summary
The discussion focuses on calculating the angular momentum of a particle with a mass of 0.01 kg rotating at an angular speed of 2 rad/s in a circle of radius 0.8 m. The initial calculations provided suggest that the rotational inertia (I) is 0.0064 kg*m^2, leading to an angular momentum of 0.128 kg*m^2/s. However, there is a correction regarding the units, as the correct unit for angular momentum should be kg*m^2/s, excluding radians. The clarification emphasizes the importance of using the proper units in physics calculations.
fro
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Somewhat confused about this problem and need some clarification:

Problem: A particle of mass 0.01kg rotates with angular speed of 2 rad/s in a circle of radius 0.8m. What is its angular momentum?

I think the answer should be:
I = 0.01kg X (0.8m^2) = 0.0064 kg/m^2.
w = 2 rad/s.
Therefore, angular momentum = 0.0064 kg/m^2 X 2 rad/s = 0.128 kg*rad/m^2*s.

Am I on the correct path?
 
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fro said:
I think the answer should be:
I = 0.01kg X (0.8m^2) = 0.0064 kg/m^2.
w = 2 rad/s.
Therefore, angular momentum = 0.0064 kg/m^2 X 2 rad/s = 0.128 kg*rad/m^2*s.

You are correct in your calculations, but not in your units. The unit for rotational inertia is kg*m^2, which is what your math would indicate. Also, the radians are generally not included in the units for angular momentum, so you should come up with an answer in the form kg*m^2/s.
 
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