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

Answer:

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

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

$P_{avg} = \frac{E_{total}}{t} \\\\P_{avg} = \frac{E_{step}*S}{t}\\\\\frac{P_{avg}}{E_{step}} = \frac{S}{t} \\\\\frac{S}{t} = \frac{80}{31.2} \\\\\frac{S}{t} = 2.564 \ m/s$

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