Calculate the power output (in Watts) under resting condition of the standard hu

Question

Calculate the power output (in Watts) under resting condition of the standard human body? LIST/DESCRIBE ALL THE ASSUMPTIONS!   Show all work (10 pts).

Can a Snickers bar provide all the energy your brain needs to get you through a 2-hour exam? Yes   /   No?

AND calculate how much energy (kcals) would be supplied to the brain. Assume all the carbs in the bar are glucose (4 kcals/g) and that all reach the brain. (Note: 2.7 oz Snickers Bar has 35g carbs; there are 4.184 joules in a calorie). LIST/DESCRIBE ALL THE ASSUMPTIONS!

Calories - Joule: , kg •m? |J= kg m” =N•m = Pa-m' = w.s = c.v 1Joule is -energy released by a medium sized apple falling 1 meter Specific Heat of Water: 1 Calorie = 4.1855 J= "15° Calorie" 4.184 J = "Thermochemical calorie" 4.190 J = "Mean calorie" (0 – 100 °C)

Explanation / Answer

BMR /Basal metabolic rate : It is the total energy per unit time by endothermic animals at rest , means for humans it is the amount of energy per unit time to keep body functions while on rest.

So, power output under resting condition means BMR.

Equation used to calculate BMR :

Revised equations by miffin and st.Jeor in 1990 ( orginal modification of Harris- Benedict equations )

Men's BMR = (10 x weight in kg ) + (6.25 x height in cm) -- (5 x age in years ) + 5

Women's BMR = (10 x wt in kg ) + (6.25 x height in cm ) -- (5 x age in years ) -- 161

Let's assume weight of a moderately active man as 189 pounds, age 35 and height 6.4 feet

Then the calculated BMR = 3035.50 calories per day

1 Calorie = .001163 wh (watt hr)

So BMR = 3.53028 watt hr

Can a Snicker bar provide energy for your 2 hour exam ?

Ans : No

Reason : -- carbohydrates = 35 g x 4 =140 kcal ( I g = 4 kcal )

Glucose = 35 x 4 ( 4 kcal per grams) =140 kcal

Total energy from chocolate is 140 kcal

1 kcal is 4.184 joules

So 140 kcal means 1,171.52 Joules

Approximately a human body uses 97.2 joules per sec means 5,832 joules per min.

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