How many grams of carbohydrate does a person of mass 75 kg need to metabolize to climb five flights of stairs (15 m height increase)? Each gram of carbohydrate provides 17.6 kJ of energy. Assume 10.0% efficiency—that is, 10.0% of the available chemical energy in the carbohydrate is converted to mechanical energy.
g
What happens to the other 90% of the energy?
Could someone show me how to do this please. Thanks. I have a hard time figuring it out.
physics - Count Iblis, Friday, June 8, 2012 at 2:07pm
The person needs to do an amount of work of W = 75 kg * 15 m * 9.81 m/s^2 against gravity.
Per gram of carbohydrates, you have available 10% of 17.6 KJ to do mechanical work, so you need to divide W by 1.76 KJ to find the amount of carbohydrates needed in grams.
The other 90% converted to heat.
part a i tried it and it gave me 11036.25 that was wrong i put 110.36 that was wrong so i don't know how to do it and the answer has to be in g???please help. Thank you
How many grams of carbohydrate does a person of mass 75 kg need to metabolize to climb five flights of stairs (15 m height increase)? Each gram of carbohydrate provides 17.6 kJ of energy. Assume 10.0% efficiency—that is, 10.0% of the available chemical energy in the carbohydrate is converted to mechanical energy.
g
What happens to the other 90% of the energy?
Could someone show me how to do this please. Thanks. I have a hard time figuring it out.
physics - Count Iblis, Friday, June 8, 2012 at 2:07pm
The person needs to do an amount of work of W = 75 kg * 15 m * 9.81 m/s^2 against gravity.
Per gram of carbohydrates, you have available 10% of 17.6 KJ to do mechanical work, so you need to divide W by 1.76 KJ to find the amount of carbohydrates needed in grams.
The other 90% converted to heat.
part a i tried it and it gave me 11036.25 that was wrong i put 110.36 that was wrong so i don't know how to do it and the answer has to be in g???please help. Thank you
No one has answered this question yet.
To calculate the amount of carbohydrate needed to metabolize, you need to follow these steps:
Step 1: Calculate the work done against gravity
The formula for work done against gravity is W = mgh, where m is the mass, g is the acceleration due to gravity (9.81 m/s^2), and h is the height increase.
For a person with a mass of 75 kg and a height increase of 15 m, the work done against gravity is:
W = 75 kg * 15 m * 9.81 m/s^2 = 11,018.25 J
Step 2: Calculate the amount of carbohydrate needed
Each gram of carbohydrate provides 17.6 kJ of energy. However, you mentioned that only 10% of the carbohydrate energy is converted to mechanical energy. So, we need to account for this efficiency.
The available energy in carbohydrates to do mechanical work is calculated as:
Available energy = 0.1 * 17.6 kJ = 1.76 kJ
Since we want the answer in grams, we need to convert 1.76 kJ to J by multiplying by 1000:
1.76 kJ * 1000 = 1760 J
Finally, divide the work done against gravity by the available energy in carbohydrates:
Amount of carbohydrate needed = Work done against gravity / Available energy
Amount of carbohydrate needed = 11,018.25 J / 1760 J = 6.26 grams
So, a person with a mass of 75 kg would need to metabolize approximately 6.26 grams of carbohydrate to climb five flights of stairs with a 15 m height increase.