Please consider this question: A train derailed while rounding an unbanked curve of radius 150 meters. A passenger on the train during the accident noticed that an unused strap was hanging at about a 15 degree angle to the vertical just before the derailment. How fast was the train moving at the time of the derailment? This is based on problem 27 of chapter 5 of Wolfson's Essential University Physics (3rd edition). The book itself has the answer 58 km/hour, which seems wrong to me. I keep coming up with something more like 71 km/hour. Can you make any sense of that?

Please consider this question: A train derailed while rounding an unbanked curve of radius 150 meters. A passenger on the train during the accident noticed that an unused strap was hanging at about a 15 degree angle to the vertical just before the derailment. How fast was the train moving at the time of the derailment? This is based on problem 27 of chapter 5 of Wolfson's Essential University Physics (3rd edition). The book itself has the answer 58 km/hour, which seems wrong to me. I keep coming up with something more like 71 km/hour. Can you make any sense of that?