second part of the question. Thanks for the help. Course Home (HW 1 (Ch. 1-3 Com
ID: 715426 • Letter: S
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second part of the question. Thanks for the help.
Course Home (HW 1 (Ch. 1-3 Combining Ikdeas 4 Consaets I B Tae Part C The lstel of an onergy bar wih a mass of 73 g lsts the nution lacts as 39 r of cabehydiale, 6 ig of fat, and 80 gal piotain If you obtain 149 k.J, how many grams of the energy bar did you eat? Express your answer to two significant figures and include the appropriate u An energy bar contains carbohydrate, fat, and protein. alue Units Submit Request Answer Part D It you are walking and using anangy at a rate of 840 k.I/h how many minutes will yo the energy from tmo enorgy bars? Express your answer to two significant figures and include the appropriate unit Value Units Request Answer Pscovide FeedbackExplanation / Answer
Ans. # Step 1: Calculate calorific value (CV) of the bar-
Energy from cabs = Mass of carbs x CV of carbs
= 39.0 g x (16.736 kJ/g) = 652.704 kJ
Energy from fats = Mass of fats x CV of fats
= 6.0 g x (37.656 kJ/g) = 225.936 kJ
Energy from proteins = Mass of proteins x CV of proteins
= 0 g x (16.736 kJ/g) = 0 kJ
# Total energy = Energy of (carbs + fats + proteins)
= 652.704 kJ + 225.936 kJ + 0 kJ = 878.64 kJ
# Given, mass of bar = 73 g
So,
CV of bar = Total energy content / Mass of bar
= 878.64 kJ / 73 g = 12.04 kJ/ g
# Step 2: Part C:
Required mass of bar = Required energy / CV of bar
= 149 kJ / (12.04 kJ/ g) = 12.38 g = 1.2 x 101 g
# Part D: Total energy from two bars = 2 x Total energy of a bar
= 2 x 878.64 kJ = 1753.28 kJ
# Now, required time = Energy from bar / Energy expenditure of running
= 1753.28 kJ / (840 kJ / hr)
= 2.087 hr
= 125.34 min = 1.3 x 102 min
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