Energy for our activity is provided by the chemical energy of the foods we eat.
ID: 1997236 • Letter: E
Question
Energy for our activity is provided by the chemical energy of the foods we eat. The absolute value of the rate of conversion of this chemical energy into other forms of energy (delta E/delta t) is called the metabolic rate. The metabolic rate depends on many factors a person's weight, physical activity, the efficiency of bodily processes, and the fat muscle ratio. The table lists the metabolic rates of people under several different conditions and in several different units of measure: 1 kcal = 1000 calories = 4186 J. Dieticians call a kcal simply a Cal. A piece of bread provides about 70 kcal of metabolic energy. hour of heavy exercise a 68-kg person metabolizes 600 kcal - 90kcal = 510 kcal more energy than when Typically. reducing kilocalorie intake by 3500 kcal (either by burning it in exercise or not consuming it in first place) results In a loss of 0 45 kg of body mass (the mass is lost through exhaling carbon dioxide - the duct of metabolism) Suppose that a 68-kg person walks for 1 hour each day for a year, expending 90,000 extra kilocalories of metabolic energy (in addition to his normal resting metabolic energy use). What approximately is the person's mass at the end of the year, assuming his food consumption does not change? Express your answer to two significant figures and include the appropriate units.Explanation / Answer
Rate of energy consumption of 68 kg person for walking (3mph) = 240 ( data from the table)
Total comsumption energy of a 68kg person in one year =240*365=87600 Kcal (as per data)
but actually comsumed is =90000K cal
Difference =90000-87600=2400Kcal
Extra energy used by the 68 Kg person in each day = 2400/365=6.6 Kcal per day
if the rate of energy used by the person is 240+6.6= 246.6 per day then for one year it is 90000 Kcal
Energy required for every 1Kg mass of a (68kg) person for walk is = 3.5 K cal
Food consuption does not changed but he comsumed 6.6 K cal extra every day ( i.e 3.5x2)
So his mass may decrease by 2Kg
m=66Kg
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