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What is Forced (accelerated) Motion?

What is Forced (accelerated) Motion? - Physics Forum

What is Forced (accelerated) Motion? - Physics Forum. Discuss and ask physics questions, kinematics and other physics problems.


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  #1  
Old 07-20-2004, 06:10 AM
novakyu@yahoo.com
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Default What is Forced (accelerated) Motion?



Spaceman wrote:
(snip)
vectors etc..)
speed of 100 rpm)

Surely, we know what kind of creatures mathematicians and physicists
are. You give them a word, they will take its meaning, distort it, fit
it into whatever meaning they desire, and boom--there's the "true
meaning" of the same word we didn't know it had all along....

One fine example is velocity and speed. To a nonphysicist--they are one
and the same. To a physicist--it's difference between heaven and earth:
expressions such as velocity X velocity or speed*speed makes sense,
while velocity.speed does not.

That is not to say that it's a bad practice. Sure, the physicists could
invent a word, say, "zbella" that means what they mean by "velocity"
now, and they could say, "sbel" is what they mean by "speed" now--but,
do you really want to deal with those weird words? Neither do I, and I
cound myself as a physicist.

Anyway--this is just typical of the kind of confusions that could arise
in a nonscientist. When a scientist (that is, to say, a physicist)
says, "acceleration," he rarely means a change in speed (which is what
you described)--he means a change in velocity. So, to understand what
"acceleration" means, it is necessary to understand what "velocity"
means, and to understand that, it is necessary to understand what a
"vector" is, and to understand that, you must be able to draw an arrow


On a related note, this is one of the funniest math jokes I came
across:

Why do mathematicians insist on using a word that already has another
meaning?
-"It is the complex case that is easier to deal with."

Another prime example (heh--no pun intended, at least not initially) of
the word usage of those mathematicians (and physicists).

PS. Oh, BTW, I don't think physics has "real world" defined yet--so,
use it freely while you can (once the physicists have defined what
"real world" means, you won't be able to use it in any other sense
without the gestapo tracking you down and your neighbors noticing your
sudden disappearance).

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  #2  
Old 07-20-2004, 04:18 PM
Jeremy Watts
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Default What is Forced (accelerated) Motion?


<[Only registered users see links. ]> wrote in message
news:cdid0j$[Only registered users see links. ].google.com...

'velocity' and 'speed' are different things - very much in the same sense
that 'mass' and 'weight' are different. Mass is a scalar quantity, weight
is a vector. Similarly velocity is a vector and speed its scalar
counterpart.

A seemingly small pedantic difference, but in fact an extremely important
distinction. The failure in the original posters thinking is due to his
non-appreciation of the distinction between speed and velocity.


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