Calculating Distance Traveled by Semi-Trailer Truck Odometer

[Mariesa Yeoman]

Homework Statement

Semi-trailer trucks have an odometer on one hub of a trailer wheel. The hub is weighted so that it does not rotate, but it contains gears to count the number of wheel revolutions—it then calculates the distance traveled. If the wheel has a 1.02 m diameter and goes through 210,000 rotations, how many kilometers should the odometer read?

Homework Equations

I am not sure what I am doing incorrectly?

The Attempt at a Solution

If the formula is distance/rotation =π * diameter
Then,
Distance = π* diameter * rotations
Meaning,
π * 1.02 * 210,000 = 673,016.4m * 1 km/1000m = 673.02km after rounding?

 

[phinds]

π * 1.02 * 210,000 = 673,016.4m

Really?

 

[berkeman]

My calculator gives 672.93km. Maybe try again and use the Pi entry on your calculator instead of rounding it yourself? Not sure where your small error is coming in...

 

[phinds]

Oh, yeah. If you use pi = 3.142, you get his answer

 

[Mariesa Yeoman]

okay great thank you!