As we know that the wheel rotate for 5 s with constant angular acceleration
so we have
θ \(=\frac{\omega+\omega_0}2t\)
100 \(=\frac{\omega+\omega_0}2(5)\)
ω+ω0 = 40
now we know that after this it rotate with constant angular speed for t = 5 s
so now we have
θ = ωt
80 = ω(5)
ω = 16 rad/s
now we have
16+ω0 = 40
ω0 = 24 rad/s
now angular acceleration is given as
α \(=\frac{\omega+\omega_0}t\)
α \(\frac{16-24}5\)
α = -1.6 rad/s2