Question

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 (assumed to be uniform (in rad s^-1) is ______.

Options

• `pi/2`

• `pi/4`

• `pi/6`

• `pi/8`

Answer 1

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 (assumed to be uniform (in rad s^-1) is `underlinebb(pi/2)`.

Explanation:

Use ω = ω₀ + αt

Here, ω₀ = 900 rpm = `(2pixx900)/60`rad/s

ω = 0 and t = 60

0 = `(2pixx900)/60` + α × 60

α = `(2pixx900)/(60xx60)` 

= `pi/2`