A wheel is rotating at 900 rpm about its axis.When the power is cut-off it comes to rest in 1 min.The angular retardation in rad s⁻² is

Options

(a) 𝜋 / 2
(b) 𝜋 / 4
(c) 𝜋 / 6
(d) 𝜋 / 8

Correct Answer:

𝜋 / 2

Explanation:

w = 900 x 2π/60 = 30π
Angular Retardation = [final velocity – initial velocity] / time
= (30π – 0)/60 = π/2
Therefore, the angular retardation is π/2.