The best answer for hunting: center of mass. If you are unsure if you can cleanly incapacitate or kill the animal within minutes do not sling at it. When it comes to hunting small and fast is better than large and slow because it packs more energy. The reason large calibers are used in guns is that bullets can have both, but I doubt even the most fit person could manage to sling something massive very fast. I would not deer hunt with a sling. I would not boar hunt with only a sling (though if I had a boar spear in my off hand I would herd it with my sling).

1 pound is 4.4 Newtons of force in the downward direction.

If I was going to sling at anything larger than a fox I would use a compound sling to accelerate a small projectile to very high velocities with the force from the much greater length the compound sling gives me. Or I would use a bow instead.

picklepie159 wrote on Sep 22^nd, 2010 at 6:05pm:

Google is over simplified. Here is the definition from a conversion website:
Quote:

There are multiple "pounds" including the London pound, Avoirdupois pound, and the US standard "International Avoirdupois" pound. To be as accurate as possible convert from 2.20462 US pounds to 1 kilogram and then to Newtons by multiplying by the acceleration (which is 9.8 m/s² for gravity). There are 4.4 Newtons of force downward per US pound of weight.

okay man

My data comes from physics. The equation for kinetic energy is E=¹/₂mv². Arbitrarily take 2 and 5 to be the mass and velocity, and vice versa.
Equation 1:
m=2 kg
v=5 m/s
E=25 J

Equation 2:
m=5kg
v=2 m/s
E=10 J

The reason your board broke was from the inertia of the stone and the brittleness of the board.
Edited:

FWIW, Dohrewend emphasises greater momentum ie. higher mass at lower velocity, as being more lethal.

Morphy wrote on Sep 23^rd, 2010 at 7:01pm:

Oh, it isn't by far. I'll admit that.

Morphy wrote on Sep 23^rd, 2010 at 7:01pm:

If the speeds that the projectiles can be slung at are near equal then we can arbitrarily say that the 2 oz. stone is a situation where you can have both high mass and velocity. Agreed?

I would only emphasize choosing a noticably smaller projectile when the larger one is massive enough that you cannot accelerate it as fast (or apply a large enough impulse during the throw) as the smaller projectile. Choosing the smaller projectile is also only advantageous if the impact is spread out over a certain ammount of time, but not spread out to the point of softening the blow. Also there are definitely exceptions where a huge stone would be better, like extremely close range or some kind of armor on the prey animal (like a turtle, armadillo, etc.). I'm an aerospace engineering student and I have absolutely no knowledge of anatomy (besides that the hip bone is connected to the leg bone) so I can't say anything about the torque produced by the arm, acceleration, or anything anatomically possible. I'll take your word for all of it. Like my crazy Calculus I professor says, "Don't write what you don't know!"

Aussie wrote on Sep 23^rd, 2010 at 11:24pm:

Then I respectfully withdraw my statements.