Question

An automobile tire is rated to last for 60,000 miles. to an order of magnitude, through how many revolutions will it turn?

Answer 1

Let the average diameter of the automobile tire is about 2 feet. Therefore its circumference is  $2 feet\times \pi =6.29 feet$.

Now we have to convert an automobile tire is rated to last for 60,000 miles in to feet.

As $1 miles =5280 feet$ .

So, $60000 miles = 60000\times 5280 feet =316800000 feet$

Thus the number of revolutions,

$\frac{316800000 feet }{6.29 feet} =50365659.8 revolutions \\\\=5.0\times10^7 rev$

Hence, order of magnitude of revolutions is 7.