contestada

When you drink cold water, your body must expend metabolic energy in order to maintain normal body temperature (37° C) by warming up the water in your stomach. Could drinking ice water, then, substitute for exercise as a way to "burn calories?" Suppose you expend 450 kilocalories during a brisk hour-long walk. How many liters of ice water (0° C) would you have to drink in order to use up 450 kilocalories of metabolic energy? For comparison, the stomach can hold about 1 liter.

Respuesta :

Answer:

[tex]V=12.1622\ L[/tex]

Explanation:

Given:

  • Initial temperature of water, [tex]T_i=0^{\circ}C[/tex]
  • final temperature of water, [tex]T_f=37^{\circ}C[/tex]
  • energy spent in one hour of walk, [tex]Q=450\ kcal=450\times4186=1883700\ J[/tex]
  • volumetric capacity of stomach, [tex]V=1\ L[/tex]

Now, let m be the mass of water at zero degree Celsius to be drank to spend 450 kilo-calories of energy.

We know:

[tex]Q=m.c.\Delta T[/tex] .....................................(1)

where:

m = mass of water

Q = heat energy

[tex]\Delta T=[/tex] temperature difference

[tex]c=4186\ J.kg^{-1}.K^{-1}[/tex] = specific heat capacity of water

Putting values in the eq. (1):

[tex]1883700=m\times 4186\times 37[/tex]

[tex]m=12.1622\ kg[/tex]

Since water has a density of 1 kilogram per liter, therefore the volume of water will be:

[tex]V=12.1622\ L[/tex]

Otras preguntas