Posted by **Norah** on Sunday, August 29, 2010 at 3:56pm.

A car is moving at a rate of 65 miles per housr and the diameter of it's wheels is 2.5ft. Find the number of revolutions per minute the wheels are rotating.

I have no idea where to begin on this question. How do you find rev per min?? Can someone walk me step by step how to answer a problem this?

- L PreCal -
**drwls**, Sunday, August 29, 2010 at 4:05pm
First convert miles per hour to feet per second.

65 mph = 95.3 ft/s

The rotation rate of the wheels in radians per second, w, is

w = (speed)/(radius) = (95.3 ft/s)/(1.25 ft)

= 76.3 radians/s

Convert that to rpm by multiplying by

(60 s/min)*[1/(2 pi)] rev/rad)

729 rpm

## Answer This Question

## Related Questions

- Pre-calc - A car is moving at the rate of 60 miles per hour, and the diameter of...
- Math - A car is moving at a rate of 60 miles per hour. the diameter of the ...
- Trignometry - A car is moving at a rate of 55 mph and the diameter of its wheels...
- Honors Pre-Calculus - It is known that when a car with wheels of radius 14 in. ...
- trigonometry - A truck with 48-in.-diameter wheels is traveling at 55 mi/h. Find...
- Math - A truck with 40-in.-diameter wheels is traveling at 50 mi/h. a) Find the ...
- Trigonometry - a bicycle with 24inch diameter wheels is traveling at 15mi/hr. a...
- precalc - The wheels of a car have a radius of 11 inches and are rotating at 600...
- Math - A truck with 36-in.-diameter wheels is traveling at 55 mi/h. Find the ...
- trigonometry - A truck with 48-in.-diameter wheels is traveling at 45 mi/h. (a) ...

More Related Questions