A heavy flywheel with a rotational inertia of \(I = 4.0 \text{ kg}\cdot\text{m}^2\) is initially at rest. A string wrapped around the outer rim of the flywheel is pulled, exerting a variable torque \(\tau\) on the flywheel as a function of its angular displacement \(\theta\), as shown in the graph. Frictional forces are negligible. What is the angular speed of the flywheel after it has rotated through an angular displacement of \(10 \text{ rad}\)?