Assume that the backwards running marathon record is 3h 53min 17s.

Question

Determine the average of this 42.2km race. Express your answe in both m/s and km/h.

 

ans.(3m/s, 10.9km/h)

Answer 1

The calculation is a routine use of r = d/t once the time is converted into hours.

 

t = 3 hrs + 53 min * 1hr/60 min + 17s * 1hr/3600 = 3.888 hours.

 

42.2km/3.888h = 10.9 km/h

10.9 km/hr * 1000 m/km * 1hr/3600s = 3.01 m/s