Question

A tire on sal's car makes 13 revolutions per second while traveling down the freeway. sal's tires are 2 ft in diameter, and there are 5,280 feet in 1 mile. how far does sal drive in 1 hour? round the answer to the nearest mile. a. 28 miles b. 56 miles c. 60 miles d. 111 miles

Answer 1

Compute the speed of the car:

`(2\pi\,\rm ft)/(1\,\rm rev) \cdot (13\,\rm rev)/(1\,\rm s) \cdot (1\,\rm mi)/(5280\,\rm ft) \cdot (3600\,\rm s)/(1\,\rm h) = (195\pi)/(11) (\rm mi)/(\rm h) \approx 55.6919 (\rm mi)/(\rm h)`

So after 1 hour, Sal will have driven about 56 mi.