Circumference = 2 x pi x radius![]()
Yes, I know.
7 inch disc:
Circumference = 2 * 3.142 * 7 = 43.988 inches
Speed at 10,000 rpm = 10,000 * 43.988 * 60 = 26392800 inches per hour
12 inches per foot, 5280 feet per mile, so speed is 416.55 mph
12 inch disc:
Circumference = 75.408 inches
Speed at 10,000 rpm = 714.09 mph.
Neither of those is 357 mph. How do you get 357 mph?
EDIT: 6 inch disc would be 357 mph.
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