Posted by **alex** on Tuesday, May 22, 2012 at 11:45pm.

while running a marathon, alex is producing about 900 calories per hour. 1 calorie is 4184 j. if the specific heat of the human body is 3500 j/kg x c, how many degrees celsius would alexs temperature increase if he did not sweat and ran the marathon in 3 h and 10 min? he has a mass of 75 kg.

thank god for sweat. if alex wants to release all of the caloric energy he produced so he doesnt heat up, how many litres of sweat would he need to produce and evaporate? the heat of vaporization for the water in sweat is 2.26 x 10^6 j/kg. the density of water is 1 g/ml

- physics! -
**drwls**, Wednesday, May 23, 2012 at 1:37am
You are talking about kilocalories, not calories. (It is written as capitalized Calories when talking about nutrition and metabolic rates)

In a 3.17 hour race, the body heat generated will be

Q = 3.17h*900Cal/h*4184J/Cal = 1.19*10^7 Joules

Temperature would increase by

delta T = Q/M*C = 45.5 C

For the second question, divide Q by the heat of vaporization in J/kg. Then convert that mass to volume in liters, using the density.

## Answer This Question

## Related Questions

- Physics - If the air temperature is the same as the temperature of your skin (...
- physic problem-thermoregulation - During a dry day, a 70.0 kg athlete runs a ...
- Astronomy/Physics - I'd love thorough solutions to these problems, but simply ...
- engineering science n3...please help and explain - Heat A.5kg of steel is cooled...
- CHEM - You have a bottle of water. The water has a mass of 29 grams. You heat ...
- science - why is a burn from steam potentially more serios than a burn from very...
- physics - water has a specific heat of 4184 j(kg K). How much energy is needed ...
- Physics Problem - While running, a 70.0 kg student generates thermal energy at a...
- Chemistry - How many joules (J) are needed to increase the temperature of15.0g ...
- physics - The basal metabolic rate is the rate at which energy is produced in ...

More Related Questions