Answer:
Option C
Explanation:
Initial frequency of rotation ν
i
=1800 rpm =1800/60=30 rps
Thus initial angular frequency w
i
=2πν
i
=60π rad/s
Final frequency of rotation ν
f
=3000 rpm =3000/60=50 rps
Thus final angular frequency w
f
=2πν
f
=100π rad/s
∴ Angular acceleration α=
t
w
f
−w
i
OR α=
20
100π−60π
=2π rad/s
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