William W. answered • 05/14/23
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The circumference of a 10 in. tire is 2πr, or 20pi in.
Next, convert 130mi to in., so 130 mi x 5,280 ft/mi x 12 in/ft = 8,236,800 in.
So the tire is traveling 8,236,800 in. hr.
8236800 in/hr / 60 min/hr = 137280 in / min
So each minute, the tire is traveling 137,280 in. and it's circumference is 20 pi in.
So the RPM of the tire is 137,280 / 20pi ≅ 21,564.
If that seems like a very high RPM, it's because car tires are normally much larger than 10 in. For example, a 30 in. car tire would only need to be going around 7,188 RPM to reach 130mph.
