Checking if I did this question correctly

watchthesky30

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Sep 15, 2009
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Hi. I just want to see if I did this question correctly.

The question is:
how many revolutions will a car wheel of diameter 30 in. make as the car travels a distance of one mile?

This is what i got for the answer:
= mile = 5280 ft = 63360 inches
The wheel's circumference is 30*pi inches, so it goes that far each revolution.
63360 in/(30*pi) in/rev = 2112/pi revolutions
= ~ 672.27 revolutions

60 mph is 1 mile per minute, so the wheel would turn at 672 rpm at 60 mph.
 
watchthesky30 said:
Hi. I just want to see if I did this question correctly.

The question is:
how many revolutions will a car wheel of diameter 30 in. make as the car travels a distance of one mile?

This is what i got for the answer:
= mile = 5280 ft = 63360 inches
The wheel's circumference is 30*pi inches, so it goes that far each revolution.
63360 in/(30*pi) in/rev = 2112/pi revolutions
= ~ 672.27 revolutions

60 mph is 1 mile per minute, so the wheel would turn at 672 rpm at 60 mph.

Correct
 
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