: He squinted at the cable. It looked like 2-centimeter thick steel wire rope. From memory, the breaking strength of a 2cm steel cable was somewhere around
He looked closer. It wasn't the cable. It was the attachment point —the bolt assembly on the girder itself. It was smaller, maybe 5 centimeters across. He quickly calculated the shear stress on a single high-strength bolt. Back-of-the-Envelope Physics
"Stop the winch!" Leo screamed, thrusting the envelope into the man's hands. : He squinted at the cable
"Okay," he whispered, smoothing the paper. "Let’s see if that cable is about to snap." It wasn't the cable
The foreman looked at Leo, then at the utility bill. "You did this with a pen and a light bill?"
The foreman looked at the frantic physicist, then at the envelope covered in scratched-out numbers and coffee stains. He looked up at the girder, which gave another ominous groan. He didn't ask for a peer-reviewed study; he grabbed his radio.