I am having with this Newton's Second Law for rotation problem.?

A cylinder is rotating about an axis that passes through the center of each circular end piece. The cylinder has a radius of 0.0750 m, an angular speed of 88.0 rad/s, and a moment of inertia of 0.850 kg·m2. A brake shoe presses against the surface of the cylinder and applies a tangential frictional force to it. The frictional force reduces the angular speed of the cylinder by a factor of two during a time of 4.40 s.


(a) Find the magnitude of the angular deceleration of the cylinder.


rad/s2


(b) Find the magnitude of the force of friction applied by the brake shoe.


N





I found the first part but I can't figure out how to get the second part.





If anyone can help it would be greatly appreciated.

I am having with this Newton's Second Law for rotation problem.?
(1) angular deceleration is given by:





α = Δω/Δt = (44)/(4.4) = 10 rad/s²





(2) F(friction) = mrω² and I = mr²





So F(frictional) = Iω²/r = (0.850)(44.0)²/(0.0750)





= 21941.33 N



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