Re: Tracking of Killer Asteroids Runs Low on Money and Short on Time

On Tue, 20 Mar 2007 22:39:45 -0700, MassiveProng
<MassiveProng@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:

On Tue, 20 Mar 2007 20:05:31 -0800, John Larkin
<jjlarkin@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> Gave us:

Of course it spins. But the path of the centroid of the ball is
unchanged. It can't deviate from the track of the bullet because that
would require sideways force, and there isn't any.


Bull***! As you strike it further and further off center, there is
more and more sidereal force exerted on it.

Um, you might look up the meaning of "sidereal."


Hitting it half way to its edge (45degrees) is almost the same as
hitting it FROM a 45 degree line of fire.

The difference being what I have been trying to tell you, which is
that a LOT of the energy remains in the bullet and it gets deflected

I've said, many times, that I assume the bullet embedds itself in the
ball and is not deflected. If nothing leaves the ball at right angles
to the initial path of the bullet, no lateral momentum is available,
so no lateral motion can result. Momentum is a vector quantity and is
conserved in all directions.


Hitting it from a 45 degree angle line of fire from the ball path
brings us back to center mass strike again, BUT hitting at that same
45 degree point where the line of fire is co-linear with the ball's
line of travel is NOT a center mass strike.

Your centroid argument works with a cube, which will have a force
exerted on it opposite the line of travel of the projectile,
regardless of strike point. The off center strike does impart a spin
on the cube, but the impact energy largely remains in the same line.

A SPHERE, however, having a rounded face, will get a side force
applied as the projectile strikes further and further off center.

By your stupid assumptions, there would be no pop-ups or foul balls
in baseball, as all hits would send the ball directly opposite the
point of strike perpendicular to the bat face, when we know that is
not the case. If the baseball is hit at the 45 degree (or greater)
point UNDER the ball, one gets a pop up, even though the line of
travel the bat had was directly back at the pitcher.

Anything sinking in yet?

What sinks in is the .22 that hits the bowling ball. Pool balls and
baseballs don't sink in to each other. IT'S DIFFERENT.

John


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