### Final 2015 Question #3

Posted:

**Thu Mar 10, 2016 10:59 am**When the question asks, what is the work DONE by the air in the lungs as it expands on going from 20C to 37C,

even though the calculation would be -3.9J (in terms of the system), shouldn't the answer be 3.9J? Because "doing work" and the negative sign cancels out each other in terms of definition?

even though the calculation would be -3.9J (in terms of the system), shouldn't the answer be 3.9J? Because "doing work" and the negative sign cancels out each other in terms of definition?