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Alexandra Carpenter 1G
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Joined: Sat Jul 22, 2017 3:00 am


Postby Alexandra Carpenter 1G » Wed Jan 10, 2018 7:15 pm

In problem #9b for Chapter 8, "The internal energy of a system increased by 982 J when it absorbed 492 J of heat. (a) Was work done by or on the system? (b) How much work was done?", is there a specific reason the answer is in scientific notation, instead of just 490 J? Or is it just a preference in notation?

Audrey Goodman 1F
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Joined: Fri Sep 29, 2017 7:06 am

Re: Notation

Postby Audrey Goodman 1F » Wed Jan 10, 2018 7:39 pm

I believe it's written in scientific notation in order to show how many sig figs there are. In the question, each value has 3 sig figs, but the final answer written as 490 J shows only 2 sig figs. Writing the answer in scientific notation or writing the answer as 490. J will show the correct number of sig figs.

Andrea ORiordan 1L
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Re: Notation

Postby Andrea ORiordan 1L » Wed Jan 10, 2018 8:51 pm

You could feasibly write the answer either way as long as you included the correct number of sig figs. I believe it's just the author's preference.

Chris Lamb 1G
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Re: Notation

Postby Chris Lamb 1G » Wed Jan 10, 2018 8:57 pm

Scientific notation is often used to remove any ambiguity about the number of sig-figs.

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Re: Notation

Postby andrewr2H » Wed Jan 10, 2018 9:04 pm

Yes, so long as the correct number of sig figs is used, either way should technically be correct. Scientific notation can just be useful in avoiding having to write out a large number of zeroes and, as already mentioned, in removing ambiguity surrounding the number of sig figs.

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