Checking my answers
a disk of radius 10 cm speeds up from rest. it turns 60 radians reaching an angular velocity of 15 rad/s. what was the angular acceleration?
b. how long did it take the disk to reach this velocity?
a) α = ?
(ω2)^2 = (ω1)^2 + 2α(theta)
15^{2}= 0^{2} + 2(α)(60)
225 = 120α
α = 1.875 rad/s^2
b)
α = (ω2-ω1)/t
t = (ω2-ω1)/α = (15-0)/1.875 = 8
t = 8 s