Re: Is physics really a matter of belief?
From: Sam Wormley (swormley1_at_mchsi.com)
Date: 11/22/04
- Next message: Sam Wormley: "Re: Is physics really a matter of belief?"
- Previous message: EL: "Re: Zero Point Electron Orbit Stability?"
- In reply to: Sam Wormley: "Re: Is physics really a matter of belief?"
- Next in thread: Sam Wormley: "Re: Is physics really a matter of belief?"
- Messages sorted by: [ date ] [ thread ]
Date: Mon, 22 Nov 2004 07:58:00 GMT
Sam Wormley wrote:
> Jim Greenfield wrote:
>
>> Sam Wormley <swormley1@mchsi.com> wrote in message
>> news:<901od.368953$wV.198242@attbi_s54>...
>>
>>> Jim Greenfield wrote:
>>>
>>>
>>>> Distance is ALWAYS positive; therefore VELOCITY is always positive
>>>> ..and therefore LT's are faulty. (SR defunct)
>>>>
>>>
>>> Nope--the sign depends on coordinate system Greenfield. Negative
>>> position, velocity and acceleration are valuable (and necessary)
>>> concepts. What is the vertical acceleration of a baseball gaining
>>> height near the surface of the earth?
>>
>>
>>
>> In YOUR coordinate system, what is the distance between (-2) and (+2)
>>
>
> A typical coordinate system for vertical position in the above
> example is something like
>
> ^
> |
> +
> |
> + 2 (meters)
> |
> + 1
> |
> -----+ 0 -------------- Surface of the Earth
> |
> + -1
> |
> + -2
>
> Gravitational force in in the negative direction. The baseball gaining
> height.
>
> vertical position is *positive* and is increasing
> velocity dy/dt is *positive* and decreasing
> acceleration dv/dt is *negative* and constant (to a first approximation
> and the force of gravity varies with height.
>
> the absolute value
> |(2) - (-2)| = 4
> |(-2) - (2)| = 4
>
> The distance (displacement in the coordinate system) from
> the +2 position to the -2 position is -4
>
> The distance (displacement in the coordinate system) from
> the -2 position to the +2 position is +4
>
> You should have learned all this in the ninth grade or earlier if you are
> a typical westerner of your age.
>
>
>
>
To Help Greenfild visualize
http://www.glenbrook.k12.il.us/gbssci/phys/mmedia/vectors/nhlp.html
- Next message: Sam Wormley: "Re: Is physics really a matter of belief?"
- Previous message: EL: "Re: Zero Point Electron Orbit Stability?"
- In reply to: Sam Wormley: "Re: Is physics really a matter of belief?"
- Next in thread: Sam Wormley: "Re: Is physics really a matter of belief?"
- Messages sorted by: [ date ] [ thread ]
Relevant Pages
|
