Question

While running, a person dissipates about 0.60 J of mechanical energy per step per kilogram of body mass. If a 68 kg person develops a power of 61 W during a race, how fast is the person running

Answer 1

Answer:

Speed = 2.25 m/s

Explanation:

(Assume a running step is 1.5 m long)

Given the following data;

Energy = 0.6J

Power = 61 Watts

Mass = 68 kg

To find how fast the person running;

First of all, we would determine the total mechanical energy being dissipated by the person.

Total energy = 0.6 * 68

Total energy = 40.8 Joules

Next, we find the time;

Energy = power * time

40.8 = 61 * time

Time = 61/40.8

Time = 1.5 seconds

Finally, to find the speed;

Speed = distance/time

Speed = number of steps * time

Speed = 1.5 * 1.5

Speed = 2.25 m/s