Comments

@877CashNow, dividedalliance is correct. Here is why: while referring to a horizontal acceleration, left and right, it is important to note that left will be negative and right will be positive, left deemed to be "going backwards;" however, when in physics you refer to vertical motion, up being positive and down being negative, you must say negative for gravity since gravity always pushes down upon you. It makes sense, afterall have you ever heard a plane go up 100 meters?

@seanrhagen, you are the most correct person here and they ignored you. Relativity matters guys. Physics is no joke and numbers don't lie. With a reference point being the max point of the jump gravity would be going 'away' thus seeming positive. At the min point being the ground gravity would be accelerating the object towards it, the '0' and thus would seem negative. that being said acceleration has a direction period, as it exists purely as a vector and never as a scalar. In the formulas (most likely vectors or kinematics) you see the negative in front of acceleration only because it is in 'reference' to the effect on a velocity (slowing down or speeding up) to the point where it can reverse the direction the object initially went.

@Commandshark, A negative doesnt mean the same as it does in physics. If I gave you a problem that had one object moving up and one moving down, how would you be able to differentiate in terms of solving an equation? You use negative to refer to a direction. A negative can represent an opposing distance. For example a car moving at 30 mph to the left with an x Newton for collides with a car moving 40 mph to the right with a yNewton force and they stick together. If asked for to solve for certain things you would refer to the left as a negative number since they are not in the same direction. Sorry its late and i cant think of a solid example, i hope this clarified it for you.

@877CashNow, First, I must say that like seanrhagen has said and mathematician has also stated, it depends on the situation. For you to say gravity is never referred to as negative is incorrect. Second a negative in a lot of physics problems refers to different directions. Again, some questions asked need to differentiate between two different directions. A good example of this is inelastic and elastic collisions. While that doesnt really use gravity per say, the idea is still the same. In this picture, you are correct the negative is not really needed for gravity, but it isnt wrong, it is just stating the direction, but i feel that it is implied at this point.

@Mathematician, No, thank you for pointing it out. When having an argument it is important to show when someone isnt being clear enough or may be lacking information. This tends to happen when its late at night and I forget what I have said and have not said haha. But to summarize I agree with you the most. You said it in words I fail to possess at the moment. Well said good sir/madam.

@airguitarpro, yup i caught that at the end and figured it was just an error because of how late it is. No problem, i get what you're saying just didn't see it used correctly. In mathematics negative distances would be relative to a reference point (i.e train A and train B relative to a train station considered the 0) and the resulting calculations would involve seemingly 'negative distances' because you are in a zero sum game when it comes to collisions in mathematics!

@Mathematician, Yep! Also, upon looking up this conflicting question, I have been reassured that you can have a "negative" acceleration, velocity, distance, and force as I have thought as long as it is indicating direction. Direction is key next to relativity of course. Since you can have 2 of any of these being in different directions. This is especially true for forces and finding a net force which can be negative. Good to know that I remember a few things from my physics class haha. Goodnight friend! It was fun having a conversation with you!

@airguitarpro, indeed. I'm glad so many funnypics users have delved into the world of phun physics. I minored in physics in college and loved every course including quantum physics and astrophysics. Calculus based physics was the best though, the kind you will see in some advanced high school physics courses (beyond conceptual physics) when we had to draw diagrams of the calculations to best understand how to use the formulas at our disposal. I still wish real life were in a frictionless vacuum lol
26 March 2014 #26March2014