Your answer would be 4.0 hz.
We need to consider for this exercise the concept Drag Force and Torque. The equation of Drag force is

Where,
F_D = Drag Force
= Drag coefficient
A = Area
= Density
V = Velocity
Our values are given by,
(That is proper of a cone-shape)



Part A ) Replacing our values,


Part B ) To find the torque we apply the equation as follow,



Answer:
Explanation:
Applying conservation of momentum
mA v0 + 0 = mA x 12v0 + mB x 92v0
11 mA = - 92mB .
mA / mB = 92 / 11
mA : mB = 92 : 11.