## Notation

$\Delta U=q+w$

Alexandra Carpenter 1G
Posts: 32
Joined: Sat Jul 22, 2017 3:00 am

### Notation

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
Posts: 31
Joined: Fri Sep 29, 2017 7:06 am

### Re: Notation

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
Posts: 52
Joined: Fri Sep 29, 2017 7:04 am
Been upvoted: 2 times

### Re: Notation

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
Posts: 58
Joined: Fri Jun 23, 2017 11:39 am

### Re: Notation

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

andrewr2H
Posts: 29
Joined: Fri Sep 29, 2017 7:05 am

### Re: Notation

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.

### Who is online

Users browsing this forum: No registered users and 1 guest