I know we have discussed this before I think, and I read about it in Aarons..
How do I explain to a student that when we choose up (+y) to be increasing, we say that the sign of g is negative, regardless of whether the ball is going up or going down.
My students seem to get that when the object is going up, g is negative. They want to make the ball going down positive g. But it stays negative because of the choice of axis.
I am at a loss because until I read Aarons I thought that it changed signs too...
Tina
Tina Fanetti
Physics Instructor
Western Iowa Technical Community College
4647 Stone Ave
Sioux City IA 51102
712-274-8733 ext 1429