A flywheel with moment of inertia 0.15 kg·m² is initially rotating ccw at 10 rad·s⁻¹. The net external torque acting on the flywheel as a function of time is described below.
• 0 ≤ t ≤ 2 s: The torque starts at 0 N·m at t = 0, increases linearly to +8.0 N·m at t = 1.0 s, and then decreases linearly back to 0 N·m at t = 2.0 s.
• 2 ≤ t ≤ 4 s: A constant −4.0 N·m torque is applied.
(a) Determine the angular impulse delivered to the flywheel during 0 ≤ t ≤ 2.0 s.
(b) Calculate the angular speed immediately after t = 2.0 s.
(c) Determine the additional change in angular momentum during 2.0 s ≤ t ≤ 4.0 s, and compute the flywheel’s angular speed at t = 4.0 s.
(d) State whether, by t = 4.0 s, the flywheel is still rotating in the original direction, has come to rest, or has reversed direction, and justify your answer.