When brakes of a car are applied, angular velocity of a flywheel reduces from 900 cycle / min to 720 cycle / min in 6 sec. Angular retardation is:

Explanation

This is the following solution.First, we need to convert the given angular velocities from cycles per minute to radians per second. We know that 1 cycle is equal to 2π radians. Therefore,Angular velocity at the start = 900 cycles/min = (900 x 2π) / 60 rad/s = 30π rad/sAngular velocity at the end = 720 cycles/min = (720 x 2π) / 60 rad/s = 24π rad/sThe time taken for the flywheel to reduce its angular velocity from 30π rad/s to 24π rad/s is 6 seconds. We can use the formula for angular retardation:Angular retardation (α) = (ω2 - ω1) / tWhere ω2 is the final angular velocity, ω1 is the initial angular velocity, and t is the time taken.Substituting the given values, we get:Angular retardation (α) = (24π - 30π) / 6 = -π rad/s^2Therefore, the angular retardation is -π rad/s^2.