average angular velocity?

Question

If a bicycle with 700mm diameter wheels is ridden 10km in 15 minutes, what is the average angular velocity (rad/sec) of the bike’s wheels during this trip?

Answer 1

v = ωr
d = vt

ω = v/r = d/rt = 10,000 m / (900s x 0.700 m) =

15.87 rad/s <- answer

Answer 2

A diameter of 700 mm translates to a perimeter of 2.2 m. Hence in a 10 km trip, the wheel rotates 4545.5 times covering 2*PI radians each time

15 minutes = 900 s

w = angle/time, where w is the angular velocity

w = 4545.5*2*PI/900 = 31.7 rad s-1