Answer:
a) Angular momentum, ΔL = 1.08 kg·m²/s
b) Angular speed, ω = 830.77 rad/s
Explanation:
a) Torque = Change in angular momentum/Change in time
Let Torque = τ
L = Angular momentum
t = time
τ = ΔL/Δt
ΔL = τ * Δt
τ = 9 N.m
Δt = 120 ms = 0.12 s
ΔL = 9 * 0.12
ΔL = 1.08 kg·m²/s
b) Angular momentum = Inertia * Angular speed
Let I = Inertia
I = 1.3 * 10-3 kg·m²
ω = Angular speed
L = I * ω
ω = L/I
ω = 1.08/(1.3 * 10-3)
ω = 830.77 rad/s