Respuesta :
Answer:
a) α = 0.338 rad / s²  b)  θ = 21.9 rev
Explanation:
a) To solve this exercise we will use Newton's second law for rotational movement, that is, torque
  τ = I α
  fr r = I α
Now we write the translational Newton equation in the radial direction
  N- F = 0
  N = F
The friction force equation is
  fr = μ N
  fr = μ F
The moment of inertia of a saying is
  I = ½ m r²
Let's replace in the torque equation
  (μ F) r = (½ m r²) α
  α = 2 μ F / (m r)
  α = 2 0.2 24 / (86 0.33)
  α = 0.338 rad / s²
b) let's use the relationship of rotational kinematics
  w² = w₀² - 2 α θ
  0 = w₀² - 2 α θ
  θ = w₀² / 2 α
Let's reduce the angular velocity
   w₀ = 92 rpm (2π rad / 1 rev) (1 min / 60s) = 9.634 rad / s
  θ = 9.634 2 / (2 0.338)
   θ = 137.3 rad
Let's reduce radians to revolutions
  θ = 137.3 rad (1 rev / 2π rad)
  θ = 21.9 rev
