Extracted text: Conceptual Example 12-9: A tragic substitution. Two walkways, one above the other, are suspended from vertical rods attached to the ceiling of a high hotel lobby. The original design called for single rods 14 m long, but when such long rods proved to be unwieldy to install, it was decided to replace each long rod with two shorter ones as shown. Determine the net force `A |2mg mg exerted by the rods on the supporting pin A (assumed to be the same size) for each design. Assume each vertical rod supports a mass m of each bridge. mg Force on pin A exerted by vertical rod Forces on pins at A exerted by vertical rods 哥昌: