Question

A wheel is rotating at 900 rpm about its axis. When power is cut off it comes to rest in 1 minute, the angular retardation in rad / sec is ___ 

(A) (π / 2) 

(B) (π / 4) 

(C) (π / 6) 

(D) (π / 8)

Answer 1

Correct option: (A) (π / 2)

Explanation:

ω_i = 2π × [(900) / (60)] = 30π rad/s

Final velocity = ω = 0

ω_f = ω_i – αt----- negative acceleration

ω_i = αt

α = (ω_i / t) = [(30π) / (60)] = (π / 2)