You complain about fire safety to the landlord of your high-rise apartment building. he is willing to install an evacuation device if it is cheap and reliable, and he asks you to design it. your proposal is to mount a large wheel (radius 0.400 m) on an axle at its center and wrap a long, light rope around the wheel, with the free end of the rope hanging just past the edge of the roof. residents would evacuate to the roof and, one at a time, grasp the free end of the rope, step off the roof, and be lowered to the ground below. (ignore friction at the axle.) you want a 90.0-kg person to descend with an acceleration of g> 4. (a) if the wheel can be treated as a uniform disk, what mass must it have? (b) as the person descends, what is the tension in the rope?