Guest Posted January 12, 2009 Report Share Posted January 12, 2009 Is it possible to have a negative speed? If so, how? If not, why not? Quote Link to comment Share on other sites More sharing options...
0 Guest Posted January 12, 2009 Report Share Posted January 12, 2009 Is it possible to have a negative speed? If so, how? If not, why not? Can't have a negative speed. Speed is the magnitude of the velocity. While velocity has direction as well as magnitude, it can be negative depending on the direction vector, but magnitude is always positive. Quote Link to comment Share on other sites More sharing options...
0 Izzy Posted January 12, 2009 Report Share Posted January 12, 2009 You can't, mostly 'cos of what Ken said. You can have deceleration though, which is measured as negative speed, but it's all relative. Honestly, can you have negative anything? Maths aside, what is there I can have something negative of? Money doesn't count, as debt is essentially math anyway. Quote Link to comment Share on other sites More sharing options...
0 Guest Posted January 12, 2009 Report Share Posted January 12, 2009 Light ? A burst through a fiber, met by an opposing 2nd pulse at hte other end - the second slows the other down (or is that just deceleration?) = negative speed.. I think ?? I may be way off - just trying to remember something from elsewhere. Quote Link to comment Share on other sites More sharing options...
0 Brandonb Posted January 13, 2009 Report Share Posted January 13, 2009 (edited) Honestly, can you have negative anything? Maths aside, what is there I can have something negative of? Money doesn't count, as debt is essentially math anyway. The only truly negative thing that I can think of is a charge. Magnets, Electrons... Negative is very real. Oh, and most anything that deals with government... the challenge with that is finding the positive Edited January 13, 2009 by Brandonb Quote Link to comment Share on other sites More sharing options...
0 Izzy Posted January 13, 2009 Report Share Posted January 13, 2009 The only truly negative thing that I can think of is a charge. Magnets, Electrons... Negative is very real. Oh, forgot about those. We've not done much on magnetism in school, but when charges are said to be negative and positive, are they actually, or is it just like "This one has this type of charge, and this one has the opposite of that, so they must be positive and negative!" Oh man, I think my brain just like, exploded. Do you know how illogical it is to think that we can have a negative charge? I mean, how is that measurable? It totally just stopped making sense to me. (This isn't to say I've stopped believing in it, but woah, brain ache.) Here's my attempt (mostly for myself) to make it make sense again... Neutron = no charge (this is very easy to accept) Proton = positive charge (taking this to mean a measurable, countable, charge. As in, "I have a positive amount of money" or "I have money that exists and can be measured) Electron = .... Hey, probably not, but what if like, there's a 0, and there's really no such thing as negative and positive, just directions from 0? Not necessarily only two (as on a number line), but an infinite amount of directions? Negative and positive are just opposite directions, and it really has nothing to do with a number being below zero, just the absolute value from it? It makes it make sense! Sort of. To me anyway. Someone should interject before I actually start believing what I just wrote. My head hurts. Quote Link to comment Share on other sites More sharing options...
0 Guest Posted January 23, 2009 Report Share Posted January 23, 2009 (edited) Oh, forgot about those. We've not done much on magnetism in school, but when charges are said to be negative and positive, are they actually, or is it just like "This one has this type of charge, and this one has the opposite of that, so they must be positive and negative!" Oh man, I think my brain just like, exploded. Do you know how illogical it is to think that we can have a negative charge? I mean, how is that measurable? It totally just stopped making sense to me. (This isn't to say I've stopped believing in it, but woah, brain ache.) Here's my attempt (mostly for myself) to make it make sense again... Neutron = no charge (this is very easy to accept) Proton = positive charge (taking this to mean a measurable, countable, charge. As in, "I have a positive amount of money" or "I have money that exists and can be measured) Electron = .... Hey, probably not, but what if like, there's a 0, and there's really no such thing as negative and positive, just directions from 0? Not necessarily only two (as on a number line), but an infinite amount of directions? Negative and positive are just opposite directions, and it really has nothing to do with a number being below zero, just the absolute value from it? It makes it make sense! Sort of. To me anyway. Someone should interject before I actually start believing what I just wrote. My head hurts. To save Izzy's head: You are right in saying that we have assigned numerical meanings (positive and negative) to something which may not be numerical. Brandonb's example of magnetism is a good example as I remember it as north and south. Left and right work equally as well for electronic charge. Negative numbers are used to help maths. 0 is an arbitrary point in many cases. Going back to the opening post, speed is regarded as a scalar quantity meaning that it has magnitute only. Velocity, however, is regarded as a vector quantity meaning that it has magnitute and direction. But, as pointed out already, direction in relation to what? Hence 0 being introduced in this scenario which then leads onto negative. Oh, and most anything that deals with government... the challenge with that is finding the positive I agree wholeheartedly (I used to work for the local government) Edited January 23, 2009 by UKJon Quote Link to comment Share on other sites More sharing options...
0 Guest Posted January 23, 2009 Report Share Posted January 23, 2009 You can't, mostly 'cos of what Ken said. You can have deceleration though, which is measured as negative speed, but it's all relative. Honestly, can you have negative anything? Maths aside, what is there I can have something negative of? Money doesn't count, as debt is essentially math anyway. Deccelertion is negative acceleration not negative speed. Both obviously representing rate of change of velocity. I agree with you on the other bit negatives are short hand notation for direction that's all. even with money the "-" merely implies who owes whom. It's the same with magnetism, charge isn't precisely negative it's just short hand for how the fields will interact, the labels could easily be anything else for example electrochromodynamics uses "colour" and North and South are still used for poles Quote Link to comment Share on other sites More sharing options...
0 Guest Posted January 23, 2009 Report Share Posted January 23, 2009 ... Why is this in the Other category? Quote Link to comment Share on other sites More sharing options...
0 Guest Posted January 23, 2009 Report Share Posted January 23, 2009 ... Why is this in the Other category?it's discussion Quote Link to comment Share on other sites More sharing options...
0 Izzy Posted January 23, 2009 Report Share Posted January 23, 2009 Deccelertion is negative acceleration not negative speed. Yeah, meant to say "negative change in speed" but realized that after the editing time limit thing. Quote Link to comment Share on other sites More sharing options...
0 bonanova Posted January 29, 2009 Report Share Posted January 29, 2009 Yeah, meant to say "negative change in speed" but realized that after the editing time limit thing. Still not quite; speed is a scalar. Acceleration is a vector; so it has a direction as well as magnitude. a = dv/dt - acceleration is the time rate of change of velocity. Quote Link to comment Share on other sites More sharing options...
Question
Guest
Is it possible to have a negative speed?
If so, how? If not, why not?
Link to comment
Share on other sites
11 answers to this question
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.