Answer:
Option C
Explanation:
Given , l= 2 kg m2
ω0 = 60 rad/s , ω =0
t=5 min=5 x60= 300 s
From the relation,
ω=ω0+αt
α=ω−ω0t
⇒ α=0−60300=−60300=−15rad/s2
for t=2 min
= 2 x 60=120 s
ω=ω0+αt
= 60−15×120=60−24
∴ ω =36 rad/s
As, angular momentum. L= l ω
substituting the values in the above relation,
We get L= 2 x36= 72 kg m2 /s