SOLUTION: A wheel of a car of radius 21cm is rotating at 600 RPM. What is the speed of the car in km/hr?

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Question 286448: A wheel of a car of radius 21cm is rotating at 600 RPM. What is the speed of the car in km/hr?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
first find out how many cm in a km
100cm/m x 1000 m/km = 10%5E5 cm/km
Now how far does the car go in 1 revolution of the wheel?
It goes 1 circumference which is
C+=+2%2Api%2Ar
C+=+2%2A3.141%2A21
C+=+131.947 cm
How far does the car go in 1 min?
600 revolutions/min
131.947 cm/rev x 600 rev/min = 79168 cm/min
Now find this in cm/hr
60 min/hr x 79168 cm/min = 4750084.1 cm/hr
Now find this in km/hr
4750084.1 cm/hr x 1%2F10%5E5 km/cm = 47.5 km/hr
check my math, though