Angular Impulse From Variable Torque

A torque is applied to a wheel that is initially at rest. The torque varies with time $t$ according to the function $\tau(t) = (2.0\ \mathrm{N \cdot m/s^2})t^2 - (0.5\ \mathrm{N \cdot m / s})t$. What is the angular impulse on the wheel during the time interval from $t=0$ to $t=4.0\ \mathrm{s}$?