- #1
riseofphoenix
- 294
- 2
KErotational = (1/2)Iω2
420 = (1/2)Iω2
420 = (1/2)I(402)
420/(402) = (1/2)I
0.2625 = (1/2)I
2(0.2625) = I
0.525 = I
0.53 = I
Last edited:
What is the moment of inertia of this rotating object?
- Thread starter riseofphoenix
- Start date
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Homework Help Overview
The discussion revolves around calculating the moment of inertia for a rotating object using the concept of rotational kinetic energy. Participants are examining the relationship between kinetic energy and moment of inertia in the context of rotational motion.
Discussion Character
- Conceptual clarification, Mathematical reasoning
Approaches and Questions Raised
- Some participants attempt to derive the moment of inertia from the rotational kinetic energy formula. Others question the validity of equating kinetic energy with angular momentum due to unit discrepancies and seek clarification on the correct expression for rotational kinetic energy.
Discussion Status
The discussion includes attempts to calculate the moment of inertia, with some participants providing feedback on the calculations. There is an ongoing exploration of the correct relationships and expressions involved in rotational dynamics, with no explicit consensus reached on the calculations presented.
Contextual Notes
Participants are navigating potential misunderstandings regarding the relationships between kinetic energy, moment of inertia, and angular momentum, highlighting the need for clarity on the relevant equations.
KErotational = (1/2)Iω2
420 = (1/2)Iω2
420 = (1/2)I(402)
420/(402) = (1/2)I
0.2625 = (1/2)I
2(0.2625) = I
0.525 = I
0.53 = I
- #2
Doc Al
Mentor
- 45,584
- 2,459
You cannot set KE = L. The units don't even match.
What's the expression for rotational KE in terms of ω?
What's the expression for rotational KE in terms of ω?
- #3
riseofphoenix
- 294
- 2
Doc Al said:
(1/2)I(v/r)?
I'm not sure if there is another equation for rotational KE
- #4
riseofphoenix
- 294
- 2
KErotational = (1/2)Iω2
420 = (1/2)Iω2
420 = (1/2)I(402)
420/(402) = (1/2)I
0.2625 = (1/2)I
2(0.2625) = I
0.525 = I
Is that right?
420 = (1/2)Iω2
420 = (1/2)I(402)
420/(402) = (1/2)I
0.2625 = (1/2)I
2(0.2625) = I
0.525 = I
Is that right?
- #5
Doc Al
Mentor
- 45,584
- 2,459
Looks good.
- #6
riseofphoenix
- 294
- 2
Thanks!