A Wheel of moment of inertia 2 k g m 2 is rotating about an axis passing through centre and perpendicular to its plane at a speed 60 rad s - 1 . Due to friction, it comes to rest in 5 minutes. The angular momentum of the wheel three minutes before it stops rotating is

Step-by-step solution

I = 2  k g   m 2 ,   ω o = 60   rad   s - 1 t = 5   min = 5 × 60 = 300   s ∝   = 0 - 60 300 = - 60 300 = - 1 5   rad   s - 2 for 2min (from starting) (2 min = 120 sec) ω = ω 0 + ∝ t = 60 - 1 5 × 120 = 60 - 24 ω = 36   rad   s - 1   a n d     L = I ω = 2 × 36 = 72  k g   m 2   s - 1