A flywheel with a rotational inertia of \(I = 2.0 \text{ kg}\cdot\text{m}^2\) is mounted on a frictionless horizontal axle and is initially at rest. A string wrapped around the flywheel exerts a variable net torque \(\tau\) on the flywheel as it rotates through an angular displacement \(\theta\), as shown in the graph. What is the angular speed of the flywheel after it has rotated through an angular displacement of \(6.0 \text{ rad}\)?