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Message: <blockquote data-quote="Umbran" data-source="post: 4920539" data-attributes="member: 177">No, it isn't.  It really, really isn't.  The two are related to the same quantities, but they aren't the same thing at all.  The difference being that in every collision energy is conserved, but the same is not true for momentum.How much energy is deposited in a target doesn't mean much in and of itself.  I can push a refrigerator across the floor, putting a whole lot of energy into it, without damaging it.  If I put the same energy into the fridge with a baseball bat, the fridge will be dented.  The difference is what a physicist calls "impluse", which is equal to the change in momentum, not in energy.I'm sorry that plain text does not allow me to write these as clearly as I would like.If m = mass, and v = speedKinetic energy = 0.5 * m * v^2.  Momentum = m * v.So, let's take some examples (data pulled from the internet - we could quibble about the details, but these are just to get the right order of magnitude.)Say we have a bullet: m= 0.02 kg, speed = 400 m/sAnd an arrow: m = 0.06 kg, speed = 40 m/s  Bullet KE = 1600 JArrow KE = 48 JClearly, the bullet has higher Kinetic Energy, by a factor of 33 or so.Bullet Momentum = 8 kgm/sArrow Momentum = 2.4 kgm/sThe bullet has higher momentum, but only by a factor of about 3.  Far more even footing than on energy.Here's where the bullet's penetrating power actually works against it.  If you're firing a modern gun with a normal bullet against an unarmored target, you *expect* it to come out the other side and keep flying.  That means it has momentum left over, that it didn't lose to the target.  While a modern arrow might pass clean through, that's the exception, not the rule.  It would be even less the rule for a more primitive arrow.  It is not so odd to imagine that the bullet hits with *less* impulse than the arrow.The gun wins not because it is so much more awesome at killing for each individual bullet, but because guns are sooooo much more convenient - you can carry more projectiles, and wing them out faster than any archer ever could, and you can do it effectively with far less training and physical conditioning. Respectfully, the 200lb pull longbow was also the exception, not the rule.  That's the Dirty Harry .357 Magnum of bows, not the usual .38 special.  An old time longbow, in general, was not notably harder pull than today's powerful bows - as you pointed out the difference in today's bows isn't the pull, but in the force needed to hold the bow once you'd drawn it.</blockquote>

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