Angular Momentum: Clarifying a Problem

[fro]

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?

 

[TheloniousMONK]

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.

 

[kyle8921]

Your calculations appear to be correct. Angular momentum is a measure of an object's rotational motion and is calculated as the product of its moment of inertia (I) and angular velocity (ω). In this problem, the particle's moment of inertia is calculated using its mass and the distance from the axis of rotation (radius). The angular velocity, in this case, is given as 2 rad/s. Multiplying these two values gives the angular momentum, expressed in units of kg*rad/m^2*s. Therefore, your answer of 0.128 kg*rad/m^2*s is correct. If you are still unsure about the concept of angular momentum, I recommend reviewing some basic principles of rotational motion and practicing similar problems to solidify your understanding.