A convenient and secure attachment point for fall protection lines is located 35 feet above ground level on the exterior wall of a building. A 20-foot safety line is available for connection to this attachment point. What is the lowest and highest level at which a work platform can be safely positioned for workers to be protected by the safety line (assume it is attached to the worker’s safety harness D-ring). State any assumptions necessary to your solution.
Asfahl, C. R., Hammer, W., & Price, D. (2004/2001). Occupational & industrial safety health management and engineering
(2nd Custom ed.). New York, NY: Prentice-Hall.