Angular Momentum: Clarifying a Problem

Click For Summary
SUMMARY

The discussion clarifies the calculation of angular momentum for a particle with a mass of 0.01 kg rotating at an angular speed of 2 rad/s in a circle with a radius of 0.8 m. The correct formula for angular momentum is derived from the rotational inertia (I) calculated as 0.0064 kg*m², leading to an angular momentum of 0.128 kg*m²/s. Participants emphasized the importance of using the correct units, noting that angular momentum should be expressed in kg*m²/s, excluding radians from the final unit representation.

PREREQUISITES
  • Understanding of angular momentum and its formula
  • Knowledge of rotational inertia and its calculation
  • Familiarity with units of measurement in physics
  • Basic concepts of circular motion
NEXT STEPS
  • Study the derivation of angular momentum formulas in rotational dynamics
  • Learn about the significance of units in physics, particularly in angular measurements
  • Explore examples of angular momentum calculations for various shapes and masses
  • Investigate the relationship between angular momentum and torque in rotational systems
USEFUL FOR

Students of physics, educators teaching mechanics, and anyone interested in understanding rotational motion and angular momentum calculations.

fro
Messages
23
Reaction score
0
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?
 
Physics news on Phys.org
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.
 

Similar threads

Replies
3
Views
2K
Replies
5
Views
2K
  • · Replies 17 ·
Replies
17
Views
1K
Replies
3
Views
2K
Replies
8
Views
2K
Replies
3
Views
4K
Replies
17
Views
2K
Replies
3
Views
2K
Replies
9
Views
3K
Replies
18
Views
7K