Day has a personal shield in the nature of an Air Densification device (which is different than Jhiaxus' fast kinetic stop device). Day sees bad guy leap from a seventh floor factory window to the ground. Day decides to jump as well, and trust that his personal shield which is good enough to with high probability stop bullets will protect him from the impact.
He does pray for God's blessing before he begins which succeeds, but there's not enough magic for him to say....fly. Its a relatively low magic world.
==Acceleration. Gravity = Mass * Acceleration Squared.
He's up in the seventh floor...30 ft for the first floor, and twenty for each one above it...130 ft above asphalt.
g is 32 ft. per second squared.
I so don't know how to do this math....
Any help....?
PT
What are you looking for?
His velocity is when he hits is 91.2 ft/s and it takes him 2.85 seconds to hit.
I saw a website which has a 125 grain bullet fired from a .357 magnum doing 583 ft. lbs. of impact.
I'm using slightly lighter .357 to compensate for the fact that this is an overall attack on the whole body rather than one pinpoint attack.
So, does this fall do more impact than 583 ft. lbs...
And thanks.
Eric
You'd better check your units. 583 ft. lbs is a measure of a moment arm for levers. i.e. 583 lbs acting on a lever arm of 1 foot, or 1 lb acting on a lever arm of 583 feet.
The units should probably be in pounds per square inch.
Sorry, you did get the units right - it is also a unit of momentum!
If you think about it as energy it helps a little. Energy is 0.5*mass*velocity*velocity
A bullet has a lot of energy even though it has a small mass because it's velocity is very high. A steam engine is quite slow, but it has a huge mass.
The question is complicated a bit more because of the very high speed of the bullet. Because the time of impact is very short there isn't the normal time for the target to transfer the energy into deformations, vibrations, etc. Thus, a bullet can penetrate things that steel normally wouldn't. (or think of it this way - a rubber sheet will shatter instead of bending when a bullet hits it.)
Anyway:
The energy of a 125 grain bullet (0.018 lbs) at 1100 ft/s is 336 ft-lbs.
The energy of a 150 lb man at 91.2 ft/s is 19,381 ft-lbs.
Energy equals one half of mass (of course this requires knowing which units go with which units, I think. This equation would be messed up if you used troy ounces of gold...? Or would it? Okay, I see, I'd have to convert it into a pound fraction) times the velocity times the velocity.
So...to keep it simple a 100 grain bullet or 50 after halving going at 1000 ft/sec would be 5000 something, and we could do the mass conversion now from grains to percent of pound if we wanted to do it in a backhanded, whacked out way.
Interesting.
I have to admit my brain is low on power right now. Just got out of bed from a much needed nap. So thats my alibi.
Eric
Or you could reason it through from a different angle.
Does the air densification shield deflect bullets, or decelerate them? If it does the former, it works by spreading the impact over the body in a way that means instead of having all of that force in one point it is much less force on every point. That would mean that it would not work against an object as large or larger than the user, such as a locomotive, or the ground, because the force is already hitting every point.
If it works by deceleration, though, then it would work equally on all points. In that case, if the user were hit by a locomotive, the engine would drive into the field and the relative velocities between the user and the locomotive would rapidly but gradually equalize--and since the locomotive has mass on its side, that means the user will in essence be picked up by the train but not harmed (the impact being absorbed) (unless he also has a way of holding his position against the force of the locomotive). It would also mean that as he approached the ground, he would be slowed, and the impact reduced in much the same way that fall impact absorption would work. It is as if he is surrounded by padding that collapses in response to pressure--wrapped in bubble wrap, say.
I would expect the former to work as a sit-mod against chance of being hit at all, and the latter to work as damage mod against damage taken, but a sit-mod works for that as well because it reduces the chance that the bullet would penetrate at all. That is, say we have a 30 point benefit from the shield. If we use it as a sit-mod and the attacker would otherwise have a 60% chance to hit, he has only a 30% chance to hit, which at annihilating level would be 30 intensities; any hit above thirty would miss. Conversely, if we use a damage mod here, any roll from 01 to 60 would be a hit, but the damage would be the roll minus 30, and thus rolls from 01 through 30 do no damage (might be felt, particularly at the high end), and the damage range is up to 30 intensities for rolls from 31 through 60. So even if it is a sit-mod, it might be there to show damage reduction, as sit-mods are easier to use than damage mods generally, and particularly as negatives.
More directly, if it were called an impact-absorbing cushion of air I would assume it reduced damage and would work, but if it were called a dense deflective shield of air I would assume it spread impact and would not work.
--M. J. Young
Its free-standing armor.
That is, it blocks bullets. But it can be pierced or simply worn down, or it can be pushed against the defender. With enough force it can be 'de-anchored' and smush the defender. Or with enough force of a different sort, it can punch holes through it.
So, I'm leaning toward the deflection.
Now, Jhiaxus's body armor was deceleration of anything above a certain speed, so you could knife him, but you couldn't shoot him. However, too much damage could override his shield. Or he could simply run out of energy.
After all, the notion that a small box is going to have enough energy to stop a locomotive....well,maybe for a little tiny fraction of time which might be enough to save the player from obliteration.
I would say Jhiaxus or Day would have been toast here.
Although I have to say that using a personal forcefield as a fall safety mechanism is really clever. If I was writing it in a book, I'd want to let the hero get away with it just so everyone would say what a smart writer I was to come up with such a neat wrinkle.
With the free-standing armour, what would stop him from crashing into the armour after the armour got stopped by the ground?
Yeah, what Graeme said.
The thing with the deceleration force field is that it would reduce the damage no matter what hit you, but would have a limit. Thus it might slow a lethal bullet -3DC to annoying, and a fatal bullet to damaging, but an obliterative locomotive would still be lethal; presumably you would slam into the front, but the decelerative function would cause you to start moving before it reached you, accelerating you swiftly enough that you hit the front of the engine with only a lethal impact.
The same would happen falling toward the ground. Somewhere it says that falls up to 5' are annoying, with each additional 10' (that is, 15', 25', 35', et cetera) raising it by a damage category, so you can calculate from there.
--M. J. Young
I think that I should maybe have an ablative effect on the armor.
PT
I can agree with the concept that in destroying the armor you reduce the impact to the wearer; however, it would not be to the total amount of damage. The impact on the armor is transferred to the wearer, and the armor is destroyed in part by being crushed between the ground and the wearer, so that impact also hits the wearer with very near full force.
--M. J. Young