Question

On applying brakes the angular velocity of a flywheel reduces from 900cycle/min to 720cycle/min in 6 second. Whai is angular retarfation

Answer 1

On applying brakes the angular velocity of a flywheel reduces from 900cycle/min to 720cycle/min in 6 second. Whai is angular retarfation....

solution : initial angular velocity, $\omega_0$ = 900 cycle/min = 900 × 2π/60 rad/s

= 30π rad/s

final angular velocity, ω = 720 cycle/min = 720 × 2π/60 rad/s = 24π rad/s

and time taken, t = 6s

using formula, $\omega=\omega_0+\alpha t$

or, 24π = 30π + α(6)

or, 24π - 30π = 6α

or, α = -6π/6 = -π rad/s² , here negative sign indicates that retarding motion. i.e., angular retardation, α = -π rad/s²