For saving energy, bicycling and walking are far more efficient means of transportation than is travel by automobile. For example, when riding at 11.0 mi/h, a cyclist uses food energy at a rate of about 420 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 2.70 mi/h requires about 240 kcal/h. It is interesting to compare these values with the energy consumption required for travel by car. Gasoline yields about 1.30 108 J/gal.(a) Find the fuel economy in equivalent miles per gallon for a person walking.1 mi/gal(b) Find the fuel economy in equivalent miles per gallon for a person bicycling.2 mi/gal

a) 349.4 mi/gal

b) 813.4 mi/gal

Explanation:

Given,

- 1 kcal = 1 nutritionist's Calorie = 4186 J

- Walking at 2.70 mi/h requires about 240 kcal/h.

- Riding at 11.0 mi/h, a cyclist uses food energy at a rate of about 420 kcal/h

- Gasoline yields about (1.30 × 10⁸) J/gal

a) Fuel economy in equivalent miles per gallon for a person walking.

A person walking burns 240 kcal/h walking at a speed of 2.70 mi/h

In 1 hour, a person burns 240 kcal walking 2.70 mi.

Converting kcal to J

1 kcal = 4186 J

240 kcal = 240 × 4186 = 1,004,640 J

This means, 1,004,640 J is burned walking 2.7 miles.

Gasoline yields (1.3 × 10⁸) J/gal

The fuel economy is then calculated.

1,004,640 J = 2.7 miles

(1.3 × 10⁸) J/gal = [(2.7 × 1.3 × 10⁸)/1,004,640] mi/gal

(1.3 × 10⁸) J/gal = 349.4 mi/gal.

b) Fuel economy in equivalent miles per gallon for a person bicycling.

A person bicycling burns 420 kcal/h cycling at a speed of 11.0 mi/h

In 1 hour, a person burns 420 kcal bicycling 11.0 mi.

Converting kcal to J

1 kcal = 4186 J

420 kcal = 420 × 4186 = 1,758,120 J

This means, 1,758,120 J is burned bicycling 11.0 miles.

Gasoline yields (1.3 × 10⁸) J/gal

The fuel economy is then calculated.

1,758,120 J = 11.0 miles

(1.3 × 10⁸) J/gal = [(11 × 1.3 × 10⁸)/1,758,120] mi/gal

(1.3 × 10⁸) J/gal = 813.4 mi/gal.

Hope this Helps!!!

their crystal patterns have been disrupted by stress

answer: at 24 february, 2014 the population gets twice of its initial population.

explanation:

since we have given that

the population for alpha city, t years after january 1, 2004 is given as

first we find out the initial population, i.e. t=0,

so, our quadratic equation becomes,

according to question, we have said that if the population has twice its initial population, then it becomes

so, time taken to reach this above mentioned population is given by

now, we know that time can't be negative so, we take t=9.149 years.

hence, at 24 february, 2014 the population gets twice of its initial population.