Question

While running, a person dissipates about 0.60 J of mechanical energy per step per kilogram of body mass. If a 52-kg person develops a power of 80 W during a race, how fast is the person running

Answer 1

The person is running at a speed of 2.564 m/s

Step-by-step explanation:

Given;

mechanical energy dissipated per kilogram per step, E/kg/S = 0.6 J/kg/S

mass of the person, m = 52 kg

power developed by the person, P = 80 W

mechanical energy of the person per step, E = 0.6 J/kg x 52 kg

`E_(step)` = 31.2 J

mechanical energy for the total step,
`E_(total)` = 31.2 J x S

P = E / t

`P_(avg) = (E_(total))/(t) \\\\P_(avg) = (E_(step)*S)/(t)\\\\(P_(avg))/(E_(step)) = (S)/(t) \\\\(S)/(t) = (80)/(31.2) \\\\(S)/(t) = 2.564 \ m/s`

Therefore, the person is running at a speed of 2.564 m/s