Question

For saving energy, bicycling and walking are far more efficient means of transportation than is travel by automobile. For example, when riding at 12.5 mi/h, a cyclist uses food energy at a rate of about 360 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 3.20 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 1.30.

A) Find the fuel economy in equivalent miles per gallon for a person walking.
B) Find the fuel economy in equivalent miles per gallon for a person bicycling.

Answer 1

a. 451.72 mi/ga

b. 1078.33 mi/ga

Step-by-step explanation:

The computation is shown below:

a. The fuel economy for a person walking is

Given that

Walking at 3.20 mi/h requires about 220 kcal/h so it is equal to

`= 220 * 4186`

= 920920 j/hr

Now

`= (mi)/(j)`

`= (3.2)/(920920)`

So,

`= (mi)/(ga)`

`= (3.2)/(920920)* 1.3 * 100000000`

= 451.72 mi/ga

b. Now

Bicycling 12.5 mi/h requires about 360 kcal/h energy so it is equal to

`= 360 * 4186`

= 1506960 j/hr

So,

`= (mi)/(j)`

`= (12.5)/(1506960)`

Now

`= (mi)/(ga)`

`= (12.5)/(1506960) * 1.3 * 100000000`

= 1078.33 mi/ga

We simply applied the above formula