Page 1 of 1

HW 15.19a

Posted: Thu Mar 08, 2018 11:31 pm
Can someone explain how to get the order of [B]?
I got exact numbers for [A] and [C] but I keep getting decimal points for [B].

Re: HW 15.19a

Posted: Thu Mar 08, 2018 11:38 pm
For [B], I used the first and third experiment since [B] is the only thing that changes then. So I write the third one over the first one:
$(\frac{3.02}{1.25})^{b} = \frac{50.8}{8.7}$
So, 3.02/1.25 = 2.416
Also, 50.8/8.7 = 5.839
I know that the order for [B] has to be a whole number so like 2 or 3. So I tried squaring 2.416 and I got 5.837. That's close enough to 5.839 so it's 2.

Re: HW 15.19a

Posted: Thu Mar 08, 2018 11:41 pm
Also I tried doing the first one over the third one and I also got 2 so it doesn't matter which one goes on top and which one is on the bottom. I just got decimals when I put the small one on top but the same answer - second order.

Re: HW 15.19a

Posted: Fri Mar 09, 2018 5:57 pm
Use log rules if the order is not obvious from observation. For this you get something like 2.416^b = 5.8 as said by the person above. use the log power rule by taking the log of both sides; this takes b down

getting b*log2.416 = log 5.8
solving for b should give a number very close to 2 indicating second order