Finding energy from Inertia and RPM

[Mike_In_Plano]

Hello,

I'm working on a generalized model for motor / gear systems in SPICE and came across something I don't understand:

Given that the inertia, J, is in kg m^2
and my base unit for angular velocity, w, is kRPM
and the basic equation for energy is E = 1/2 J * w^2

How or what is the conversion factor such that I get joules as my unit of energy?

I feel really silly on this one, I can only claim memory loss...

Thanks in advance,

Mike

 

[SteamKing]

If you convert RPM to radians/second, it's a done deal. 1 RPM = 2*pi radians/min. = 2*pi/60 rad/s

1 joule = 1 N-m = 1 kg-m^2/s^2

 

[Mike_In_Plano]

To be certain, let me read back what I think I understand -

To get energy, I convert my angular velocity to radians per second and use this as omega in:

E=1/2 omega^2 J

Correct?

 

[SteamKing]

Yes.