Question

Assume running consumes 91 calories per mile. If you run 8-minute miles, what is your average power output, in watts, during a 2-hour run?

Answer 1

0.79 Watts

Explanation:

2 hours is 2 * 60 = 120 minutes

If you take 8 minutes per mile, you can run:

120/8 = 15 miles in 2 hours

Per mile calories consumption is 91, so in 15 miles:

91 * 15 = 1365

Average Power Output is Energy by Time

Also, calories to joules is:

1 Calorie = 4.184 Joules

So 1365 calorie is:

1365 * 4.184 = 5711.16 Joules

and 2 hours in seconds is 2 * 60 * 60 = 7200 seconds

Now

Average Power Output = 5711.16/7200 = 0.79 Watts