Physics  Question
posted by Raf on .
I have this number where they give me the coordinates of 3 particles and the mass of each one of them. Afterwards, there's a force applied on 2 of those particles and they ask me to calculate the systems total moment of inertia. But then they ask me this:
If the system goes from rest and that the forces from c) are applied for 5 seconds and after that 5 seconds no more forces are exerted, how much time does the system take to perform one full rotation.
So I think I'll find the answer using
T = 2pie/w, where I'll find w by first finding my angular acceleration a = t/I
from where I can find w using w = at. Then I solve for T in the first one.
is that correct?

Calculate I total for the three particles
(I = sum of 1/2 m r^2 for all three).
Then sum torques=I * angacceleration
solve for ang acceleration.
displacement=1/2 * angacceleration*time+wi*t
where wi=angacceleartion*5sec
solve for time from the displacement equation. 
thanks bob!