Please note the example below in my text. The solution has declared UP and RIGHT (forward) as the positive directions.
However, in the calculation for normal force, they have used (9.8 N/KG) instead of (-9.8N/KG) as the value for gravity. I understand that gravity is always negative (-9.8 m/s^2).
If down was declared as the positive direction, it would’ve been acceptable to use a positive 9.8, but it wasn’t — did the book make a mistake?
Unfortunately, if -9.8N/KG was used, the answer for Fnormal would be: -163.0696, which I can’t really wrap my head around.
My main question is: why was a positive value used for gravity? Please explain!
- Attachment 1
- Attachment 2