AP EAPCET 23-Aug-2021 Shift 1 Paper

Given, moment of inertia, I =40‌kg‌m2
Initial angular frequency, ωi=50‌rpm =

50×2π

60

=

5π

3

rads−1
Final angular velocity, ωf=0rads−1
Time, t=90s
Let, α be the angular retardation and since, ωf−ωi=ωt
Therefore, α=

ωf−ωi

t

=

0− 5π 3

90

=

−π

3×18

=

−π

54

‌rad‌s−2
Hence, negative sign is for retardation.