The final speed is given as,
ω2=480πrpm
ω2=16rad/sec
The angular acceleration is given as,
α=ω2−ω1t
α=16−122
α=2rad/s2
The velocity is given as,
v=rαt
v=1×2×t
v=2tm/s
The acceleration at 0.5s is given as,
a1=v2r
a1=(2t)2r
a1=(2×0.5)21
a1=1m/s2
The acceleration at 3s is given as,
a2=v2r
a2=(2t)2r
a2=(2×3)21
a2=36m/s2