Two identical, uniform solid disks rest on frictionless bearings. In each of the following scenarios, a student applies the same constant tangential force F at the rim of the disk for a short time interval.
• Scenario A: A single force F is applied at one point on the rim.
• Scenario B: Two forces, each of magnitude F, are applied simultaneously at diametrically opposite points on the rim. Both forces act in the same sense of rotation ("counter-clockwise" when viewed from above).
Assume the disks are initially at rest, have radius R, and have the same rotational inertia about the central axle.
Throughout this question, ignore any frictional torques.
(a) For each scenario, indicate the direction of the net torque acting on the disk, if any, and briefly explain your reasoning based on the applied forces.
(b) Compare the magnitudes of the net torques for Scenarios A and B. Justify your comparison without performing explicit numerical calculations.
(c) Based on your answers above, compare the magnitudes of the angular accelerations produced in Scenarios A and B. Provide a qualitative explanation grounded in rotational dynamics.
(d) Suppose each force is applied for the same time interval △t. Rank the disks according to the final magnitudes of their angular momenta (largest to smallest). Explain the physical reasoning that supports your ranking.