El carrusel de la feria del pueblo tiene una velocidad de 2 rpm. En un determinado instante se corta la corriente y como consecuencia del rozamiento, aparece una aceleración de frenado de 0,05 rad/s2.

t = 4.19 s,   θ = 0.437 rad

Explanation:

This is an exercise in rotational kinematics in this case we indicate the angular velocity and the angular acceleration, asking for the time and the angle it takes to stop.

          w = w₀ + α t

          w² = w₀² + 2 α θ

when the system stops the angular velocity is zero

          0 = w₀- α t

          0 = w₀² - 2 α θ

          t = w₀ / α

          tea = w₀² / 2 α

let's reduce the magnitudes to the SI system

          w₀ = 2 rpm (2π rad / 1 rev) (1 min / 60s) = 0.209 rad / s

let's calculate

         t = 0.209 / 0.05

         t = 4.19 s

         θ = 0.209 2/2 0.05

         θ = 0.437 rad

explanation:

newton's third law, for every action there is an equal and opposite reaction.