If you are peddling at a rate of 50 RPM and your bike wheel is 52cm what is your speed in km/h

4 answers

50rev/min * 52πcm/rev * 60min/hr * 1km/10^5cm
(50*52π*60)/10^5 = 4.9 km/hr

and that's "pedaling" unless you're selling the bike...
1 rev = 2πr = 2π(52) = 104π cm
so you covered 50(104π) cm in 50 revolutions in 1 minute
= 5200π cm/min
= (5200π/100000) km / (1/60) hrs , since 1 km = 100,000 cm and
1 hr = 60 minutes

= 3.12π km/h
= appr 9.8 km/h
I believe bike wheels are usually sized by their diameter, not the radius.
oobleck assumed the diameter was 52 cm, I assumed the radius was 52 cm

A diameter of 52 cm makes more sense, mine would be one of those
bikes with a huge front wheel

go with ooblecks solution