# Time-dependent angular acceleration problem

1. ### Ceenaya19

8
1. The problem statement, all variables and given/known data

As a result of friction, the angular speed of a
wheel changes with time according to
dθ/dt=ω0*e^-σt ,
where ω0 and σ are constants. The angular
speed changes from an initial angular speed
Determine the magnitude of the angular
acceleration after 2.44 s.

2. Relevant equations
dω/dt = $$\alpha$$

3. The attempt at a solution
I've tried differentiating the given expression for omega in an attempt to get the angular acceleration, but that didn't work because $$\sigma$$ is undefined in the problem. I've also tried taking the ln of both sides, but that didn't work either. I tried solving for $$\sigma$$ in terms of ω and ω0, but that didn't work. Finally, I tried just assuming that the acceleration is just constant from t0 to t, but that also wasn't the right answer. So, I have no idea what to try next......

Last edited: Mar 28, 2010
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3. ### Ceenaya19

8
I still can't get it O_O