http://www.ck12.org Chapter 13. Heat
Therefore:
mg∆h= 1. 674 × 106 →( 70. 0 kg)
(
- (^81) sm 2
)
∆h= 1. 674 × 106 →∆h=^1.^674 ×^10
6
( 70. 0 kg)
(- (^81) sm 2
)= 2437. 75 → 2 , 440 m!
Most of the calories (energy) that we consume are used by our bodies even if we do not exercise or otherwise
exert ourselves physically. For example, they are used to maintain a constant body temperature and keep our heart
pumping. It turns out that about 80% of our caloric intake is used just to keep us alive. The remainder of the energy
is used to perform work, such as climbing a flight of stairs, taking a walk, eating, talking, or anything else that
requires you to use energy in your daily routine. If you use more than the remaining 20% of the energy you’ll lose
weight, since your body uses your stored fat to make up the difference. On the other hand, if you don’t use up the
remaining 20%, the excess is converted to fat and you’ll gain weight.
Illustrative Example 13.2.2
a. A dieting person decides to eliminate the cream from his coffee. If he typically drinks two cups of coffee per day
with one serving of cream added to each cup, how many calories would be saved over the course of a year? One
serving of cream (about 15 grams, or one tablespoon) contains about 20 calories.
Answer:
40 Calday× 365 days= 14 , 600 Cal
b. Assuming the person’s metabolic rate remains fixed while dieting, (highly unlikely, actually) what maximum
weight loss can be expected? One kilogram of fat contains about 8,800 calories (one pound of fat has about 4000
calories).
From part A we know that 14,600 cal were saved, therefore
14 , 600 Cal
8 , 800 Calkg =^1.^659 →^1.^66 kg(^3.^65 pounds).