Re: vector quantities and energy

[Bob Sciamanda <trebor@VELOCITY.NET>]

It should not be taken as odd to consider that one might occasionally find
it useful to define a "vector kinetic energy", as indicated in the post
below.  In fact, we do the equivalent when we add a "velocity squared" air
resistance term to free fall (where the scalar drag factor C takes the place
of the factor (1/2)*m in the KE):

m*{a} = - m*g*[k] - C*V*{V}  ,

 where {x} means that x is a vector, and [k] is a unit vector pointing
vertically up.

Bob Sciamanda
Physics, Edinboro Univ of PA (ret)
trebor@velocity.net
http://www.velocity.net/~trebor

-----Original Message-----
From: Bob Sciamanda <trebor@VELOCITY.NET>
To: PHYS-L@LISTS.NAU.EDU <PHYS-L@LISTS.NAU.EDU>
Date: Friday, January 22, 1999 11:45 PM
Subject: Re: vector quantities and energy


> How about E = (1/2)m*V^2*[v] , where [v] = a unit vector in the direction
of
> the velocity.
> This can be reduced to
> E = (1/2)m*V*( V_x*[i] + V_y*[j] + V_z*[k] )
>
> Bob Sciamanda
> Physics, Edinboro Univ of PA (ret)
> trebor@velocity.net
> http://www.velocity.net/~trebor