State an approx. amount of chemical energy “used” by your body, in one day. Your answer should be based on a recommended dietary energy input using units relevant for biological (dietary) energy.

Question

Calculate your average power rating in horsepower and Watts*. This should be based on the energy assumed above.

When running at about 10 mi/hr, an athletic human body consumes energy at a rate of about 1150W (1150 Js). For how much time must you run, to “use” 25% of your total daily energy supply? (The 1150W above accounts for total energy usage, inefficiencies, and all.)

How far will you have run in this case? (Recall that you’re running at 10 mi/hr )

*This is simply the average for the day and has nothing to do with the subsequent question where you are running at 10mph.

Answer 1

Estimate your calories used for the day (Remember that nutritional calories are actually kcal = 4184 Joules)

a) Average Power = Energy or Work / time If you use Joules for energy and seconds for times, you get J/s or Watts. Look up the conversion from Watts to Horsepower or just Google watts in horsepower.

Watts are J/s, not Js. You can solve for the time to use 25% of the daily energy dividing by the power running:

t = E/P = Energy you estimated in joules * .25 / power running in watts = seconds.

distance run = vt = (10 mi/hr) * (t in hours) t in hours = t in secs (1 hr/3600 s)