Angle in Radians

[axrw]

I've got a world problem I can't figure out. The back of the book says it's about 202.

A rear wheel and tire on a John Deere 8520 farm tractor has a 39-in. radius. Find the angle (in radians) through which a wheel rotates in 12 sec if the tractor is traveling at a speed of 22 mph.

So I started with:

linear speed = radius * angular speed

I converted 22mph to ft per second

116,160/3600 = 3.25ft * w

solving that I get:

w = 9.9282 radians a second.

Then multiply by 12 seconds:

119.1384 radians

Which is nowhere near 202. What am I doing wrong?

Thanks for the help.

 

[skeeter]

202 radians is not correct for the given information. as far as I can see, you have solved the problem correctly.

recheck the given information.

 

[axrw]

I've went back and checked the book again and it definitely says 202 for that problem, and the word problem is as I said. I guess it was just a typo then. Not helpful when trying to learn math, but oh well.

Thanks skeeter. I feel much better now.

 

[Deleted member 4993]

Looks like the problem was solved (in the book) for 21 sec instead of 12 sec.