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#1 2008-03-31 23:56:25
- mellyy
- Guest
circles
My car has travelled 60 000 km since new and has had the same set of tires all that time. How many times has each wheel rotated if the diameter of each tire is 60 cm.
Please show working 
#2 2008-04-01 00:51:57
- mathsyperson
- Moderator
- Registered: 2005-06-22
- Posts: 4,900
Re: circles
The diameter is 60cm, so the circumference of your tyre is 60π cm = 0.6π m.
Each tyre has travelled 60000 km = 60000000 m, and so they have rotated 60000000/0.6π = (10^8)/π times.
Why did the vector cross the road?
It wanted to be normal.
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