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Posted: Mon Jan 15, 2018 5:47 pm
For this problem, why is the heat added (947 kJ) negative? I thought when you add heat to a system it is supposed to be positive?
Posted: Mon Jan 15, 2018 6:18 pm
So, I think it's -947 kJ because the cylinder itself isn't absorbing the heat (then it would be +947 kJ), but rather the cooling system around it is absorbing the heat. Basically, the cylinder is giving off the heat (thus -947 kJ) that the cooling system absorbs. The wording is tricky!
Hope this helps! :)
Posted: Fri Jan 19, 2018 2:06 pm
The cylinder itself is losing energy so the heat is negative