For saving energy, bicycling and walking are far more efficient means of transpo
ID: 1495443 • Letter: F
Question
For saving energy, bicycling and walking are far more efficient means of transportation than is travel by automobile. For example, when riding at 10.0 mi/h, a cyclist uses food energy at a rate of about 440 kcal/h above what he would use if merely sitting still. (In exercise physiology, power is often measured in kcal/h rather than in watts. Here 1 kcal = 1 nutritionist's Calorie = 4186 J.) Walking at 2.80 mi/h requires about 220 kcal/h. It is interesting to compare these values with the energy consumption required for travel by car. Gasoline yields about 1.3x10^8 J/gal.
(a) Find the fuel economy in equivalent miles per gallon for a person walking.
________mi/gal
(b) Find the fuel economy in equivalent miles per gallon for a person bicycling.
________ mi/gal
Explanation / Answer
the fuel economy in equivalent miles per gallon for a person walking.
1h/ 220 k cal ( 2.8 mi/h) ( 1 k cal/ 4186 J)( 1.30 * 10^8 J/ gal) = 395.25 mi/gal
(2)
the fuel economy in equivalent miles per gallon for a person bicycling
1h/ 440 k cal ( 10mi/h) ( 1 k cal/ 4186 J)( 1.30 * 10^8 J/ gal) = 705.8 mi/gal