Test 1, #7 and General Question about Heat Transfer

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Diane Bui 2J
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Joined: Sat Jul 22, 2017 3:00 am

Test 1, #7 and General Question about Heat Transfer

Postby Diane Bui 2J » Mon Feb 12, 2018 2:32 am

I've had different answers from different TA's about this, but does anyone know what the signs are for qsys and qsurr for questions like #7 on the test? I thought that since the ice is gaining heat and the water is losing heat, the equation should be -qice = +qtea. I got the right answer doing this method, but other TA's have pointed out that it should be +qice = -qtea, and I am a bit confused.

Belle Calforda3f
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Joined: Fri Sep 29, 2017 7:07 am

Re: Test 1, #7 and General Question about Heat Transfer

Postby Belle Calforda3f » Mon Feb 12, 2018 10:10 am

your statement is right, but when you wrote the equation the signs are mixed. Your Ta is right with the signs and you are right when you say the ice is gaining heat and the tea is losing heat. But, to show the "release" of heat from the tea it it is -qTea.

aTirumalai-1I
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Re: Test 1, #7 and General Question about Heat Transfer

Postby aTirumalai-1I » Mon Feb 12, 2018 2:40 pm

Conceptually, that would make sense, but when you're solving the problem, I don't think it really makes a difference (because you can technically just multiply both sides of your equation by -1 and get the other version).


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