Quote:
Originally Posted by Stuck686  2) if the 8inch radius tires on a car are rotating at 600revs per minute, how fast is car going mph ? |
what is the circumference of the tire?
C = 2pi*r = 2pi(8) = 16pi inches. or 50.265 inches
it makes 600 revs per minute, so the distance traveled in one minute is 600*C = 9600 inches per minute
but one minute is 1/60 th of an hour. so the distance travelled per hour is:
60*9600 in/h = 576000 inches per hour
now we have to convert inches to miles, i don't know that off the top of my head, so let me consult the all-knowing Google....
And the Google says: 1 inch = 1.57828283 x 10^-5 miles
so the car travels at 576000(1.57828283 x 10^-5) mph = 9.09 mph