Find angular accleration to find torque

[pully89]

Ok, I have a a motor, so I know the speed in rev/s. The motor is going to power a wheel, so I have a second moment of area?, (I), and I want to calculate the torque. I know I can do this by using T=I*$$\alpha$$. The speed of the motor is 2500 revolutions per second. So $$\omega$$ is 2$$\pi$$f, which is 261.8 radians per second, but from here I am confused on how to work out the angular acceleration, although I think that $$\alpha$$=$$\Delta$$$$\omega$$/$$\Delta$$t, but I'm still not sure how to get alpha, can anyone help?

 

[tiny-tim]

welcome to pf!

hi pully89! welcome to pf!

(have an alpha: α and a delta: ∆ and a pi: π and a tau: τ and an omega: ω )

if ω (angular speed) is constant, then α (angular acceleration) is zero

the relevant equation balances the torque in with the torque out, and really has almost nothing to do with I (the mass moment of area, or moment of inertia)