Sparky Bill PE
Senior, Master, Professional, Licensed Electrical
I keep getting 91@-15 degrees for Ic and I don't know what I'm doing wrong, I got Ia and Ib correct.
Cram for PE actual book Sym Comp 3.1.2 problem 1. Help please
- Thread starter Sparky Bill PE
- Start date
Help Support Professional Engineer & PE Exam Forum:
Sparky Bill PE
Senior, Master, Professional, Licensed Electrical
For Ic I'm doing the following forumula:
Sparky Bill PE
Senior, Master, Professional, Licensed Electrical
Yeah i was getting -158, just showed -15 on my calculator and i wasn't scrolling over enough because it wasn't saying positive 21 like the book lol.
@Cram For The PE Do you have a link to the eratta's for all your materials?
Cram For The PE
Well-known member
- Joined
- Sep 1, 2019
- Messages
- 83
- Reaction score
- 23
21° is a typo. It should be -158°. This was a misuse with my calculator. As you know, when the resultant lies in the third quadrant your calculator can trick you if you have it set wrong. If i break them all down you see the following:
44.99+53.62j-80-50-86.6j=-85-32.9j
you can see from -85-32.9j that the resultant must lie in the third quadrant. So having it as 21° is not true. It is really 180° out from 21°. If you add the vectors you will see. Below is a to scale drawing of the vectors.
Thank you for bringing this to my attention. I will get it fixed in the next edition.
44.99+53.62j-80-50-86.6j=-85-32.9j
you can see from -85-32.9j that the resultant must lie in the third quadrant. So having it as 21° is not true. It is really 180° out from 21°. If you add the vectors you will see. Below is a to scale drawing of the vectors.
Thank you for bringing this to my attention. I will get it fixed in the next edition.
