Two wheels have the same mass and radius of 5.0 kg and 0.38 m,respectively. One has (a) the shape of a hoop andthe other (b) the shape of a solid disk. Thewheels start from rest and have a constant angular acceleration with respect to a rotational axis that is perpendicular to theplane of the wheel at its center. Each turns through an angle of 12rad in 8.4 s. Find the net external torque that acts on each wheel.