Re: impulse/momentum

[Brian Whatcott <betwys1@SBCGLOBAL.NET>]

At 01:23 AM 12/12/2003, you wrote:
> >This one is from Halliday Resnick and Walker, problem 10.17, which I
> >quote:  "A stream of water impinges on a stationary 'dished' turbine
> >blade.  The speed of the water is v, both before and after it strikes the
> >curved surface of the blade, and the mass of water striking the blade per
> >unit time is constant at the value u.
>
> "speed of the water is v, both before and after"  Wow. Very strange water.
>
>
> Jim Green


Jim notwithstanding, if we accept speed as a scalar and velocity as a vector,
which (despite list misgivings) is often  allowed to take negative values in
one dimension, then specifying an eastward speed 'x' as a velocity of x1
and a westward speed of 'x' as a velocity of -x1  leads to a change of velocity
 given by the difference of the velocities, or  x - -x = 2x

This does not seem to be specially controversial.


Brian Whatcott    Altus OK    Eureka!