The discussion revolves around understanding the signs associated with forces in the context of net force equations, particularly in scenarios involving inclines and horizontal surfaces. The original poster seeks clarification on when to assign positive or negative signs to friction and weight components.
Participants are actively engaging in the discussion, with some suggesting that the assignment of signs is a matter of choice based on the defined coordinate system. There is an acknowledgment of the relationship between normal force and weight components, indicating a productive exploration of the topic.
There is an emphasis on the need for balance between forces, particularly the normal force and weight components, as well as the potential variability in definitions based on individual setups.
JaWiB said:You get to choose which direction is positive and which is negative. Typically, for inclines you choose axes that are aligned with the incline, and the direction down the ramp is most often negative, but you can choose down the ramp to be positive and up to be negative just as well.
ideasrule said:Weight parallel has to be negative, yes, but why does the perpendicular weight have to be negative? You can define it as positive if you want.