# Penetration testing...cheap and easy



## ruthiexxxx (Sep 15, 2012)

In a thread I was reading recently (forgotten who/where I'm afraid) the guy said that, in pre-chrony days, people used to test power by penetration into magazines, i.e. how many pages would the ammo pass through. Yay...a quantifiable test procedure!

I tried it with the fattest, glossiest magazine I could find but that was no help as everything passed straight through it, from hexnuts to the big lead ovals.

So then I thought of telephone directories. Perfect ! Our local one is 450 pages so i hung it from the backstop. With the rebar 'lobrounds' and starship I haven't fully penetrated one yet but got to 350 pages. If I'm very brave and use full butterfly i reckon I should be able to shoot right through it. [ A little nervous of this as the last lobround I shot from the starship at a tad more than half butterfly i actually felt the wind on my cheek...and when the wind is generated by 20 grammes of very sharp steel it generates a certain anxiety!]

I need more phone books now (it didn't last long!) but it should be a reasonably scientific way to calculate the optimum length for a lobround to maximise penetration and to make comparisons with other types of ammo.
Even if one has a chrony there seems to be utility in this approach. A chrony can tell us the speed, enabling calculation of the FORCE of impact. It cannot make a comparison of penetration.

We tend to think of slingshots as being effective in blunt force trauma but not in penetration. I think we can have both


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## benzidrine (Oct 14, 2013)

I'd recommend shooting at a slight angle to the target to significantly reduce the chance of a rebound coming towards you.

I've thought about using phone directories for this but I don't think physical phone books are still around where I live. Haven't seen one in ages. I'll probably use jugs of water if i ever do it.

Since you are using rebar anyway, you could try gluing cotton wool to the end and sharpening the point. I think you will get much better penetration that way.


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## Aussie Allan In Thailand (Jan 28, 2013)

Maybe I misread, but did it go clean through ?...

Interesting test though; but the degree of overkill, zombies or animals

What is the point ?...

Furthermore phonebooks in no way simulate flesh and bone though.

As over penetration none of us need anything going clean through a prior living creature.

Going in, expending all energy, creating HUGE damage, a big yes, going all the way through, nah.

Just my 2 pence worth on things, as I think we are on similar tracks on some things ruthiexxxx.

Cheers Allan


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## ash (Apr 23, 2013)

Water filled soda cans lined up in a row is another fairly reliable measure. I've seen six blown through more than once.

I've considered phone books before, but like Benzidrine, haven't seen one for a while.


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## Crac (Mar 3, 2013)

I would look at plumber's sealer sold as "duct seal" or "plumber's mait" over here.
http://www.screwfix.com/p/plumber-s-mait-750g/14477?_requestid=107105

I'll send more by PM.

I'd also add:

http://en.wikipedia.org/wiki/Ballistic_pendulum


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## Aussie Allan In Thailand (Jan 28, 2013)

Ruthiexxxx, Any problem is just a solution waiting to be found.

Take your Slingshots and a good knife on a road trip; find some reasonably fresh road kill, and let the penetration testing begin.

Problem solved !!!! 
With real results to have real confidence in.

All it takes is a little thinking, about real solutions, to real problems.
Rather than artificial tests which produce artificial results not applicable to living creatures.

Cheers Allan


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## ruthiexxxx (Sep 15, 2012)

Aussie Allan In Thailand said:


> Maybe I misread, but did it go clean through ?...
> 
> Interesting test though; but the degree of overkill, zombies or animals
> 
> ...


No ... so far I've only penetrated 350 pages of the 450. As i said I think full butterfly would easily do it but I think I might just shorten the bands an inch instead to get that last ounce of 'oompty'.

The advantages of the 'lobrounds' as I see it is that they offer a considerable degree of penetration. Surely this means that ALL of the kinetic energy is visited upon the target...otherwise there is a lot of residual energy wasted in the ricochet.

No, paper is not an exact equivalent of flesh...BUT these tests are COMPARATIVE ! If, for example 16mm lead makes little penetration into the phone book (or a thick paperback would do) but a lobround goes in an inch then one should surely expect a similar differential if used on, say, zombies

I LIKE overkill...it gives me confidence 

No, I have not said that I wish the rounds to pass straight through a living organism (or undead) ...just sufficient penetration to do the job. I think you have misread my post.

Take ,for example, Madison Parker's killing a deer with a headshot. I believe that he uses largish lead. I am sure that a lobround at the same velocity would do the job more effectively as it does not rely on blunt force trauma alone.

"Going in, expending all energy, creating HUGE damage, a big yes, going all the way through, nah." My sentiments exactly amigo!


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## HOE (Nov 13, 2010)

I've been using these thick unwanted books, (phone book, thick investment/company reports). By comparison, phone book can't match with investment reports, the paper used in those reports are much thicker and harder.

I love overkill as well, it ensures a kill.


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## ruthiexxxx (Sep 15, 2012)

Aussie Allan In Thailand said:


> Ruthiexxxx, Any problem is just a solution waiting to be found.
> 
> Take your Slingshots and a good knife on a road trip; find some reasonably fresh road kill, and let the penetration testing begin.
> 
> ...


Just like you amigo I am content to test mainly on thick steel. It may be 'artificial' but then it's a lot tougher than flesh


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## ruthiexxxx (Sep 15, 2012)

Crac said:


> I would look at plumber's sealer sold as "duct seal" or "plumber's mait" over here.
> http://www.screwfix.com/p/plumber-s-mait-750g/14477?_requestid=107105
> 
> I'll send more by PM.
> ...


I'll look forward to your PM amigo

But the ballistic pendulum would only tell me (like with Joerg) how much FORCE was delivered. It cannot measure penetration. Though it occurs to me that if the device was set up firstly with a steel plate that would allow no penetration and then subsequently with a softwood facing then a comparison should give some idea of how much potential energy can be accessed.


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## Aussie Allan In Thailand (Jan 28, 2013)

The comparision to lead NOT penetrating is totally misleading.

The fact it does not penetrate is a good thing actually; as it means that it "dumps" all it's energy at the point of impact
.
Making it a near perfect blunt force trauma projectile, as it expends it's total energy very quickly upon contact; ensuring the target "thing" is massively damaged.

A skull struck would crack like an egg shell I am certain with 15to 20 grams of lead or more.
As to my self guided, or not, lead filled hex nuts, at 30 grams; well I leave the damage they would do any boney surface to your imagination.
But it would not function as nature designed after being struck, that is for certain.

Cheers Allan


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## ruthiexxxx (Sep 15, 2012)

ash said:


> Water filled soda cans lined up in a row is another fairly reliable measure. I've seen six blown through more than once.
> 
> I've considered phone books before, but like Benzidrine, haven't seen one for a while.


It sounds a great test...but would be rather messy in our indoor range  And what poor sod would have to poison themselves with the chenical nightmare of those 'soft drinks' ?

Sounds like phone books are only available in this backwater now but any thick paperback would do, or HOE's investment reports. From an experimental perspective it only matters that like is contrasted with like


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## ruthiexxxx (Sep 15, 2012)

"
A skull struck would crack like an egg shell I am certain with 15to 20 grams of lead or more."

I'm sure it will Allan. But presumably we are both making lobrounds for some reason ??


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## Aussie Allan In Thailand (Jan 28, 2013)

Yea funny that,

It only takes an intermediate knowledge of A & P ( Anatomy & Physiology) to know the make up of vital organ locations of most mammals/zombies.

Along with cervical vertebrae joints/nerve path way break off points for various degrees of paralysis, be it para or quadra plegia.
Oh there are only 7 of these cervical vertebrae.
So it could be near enough is good enough; and oh dear I only meant partial paralysis, so sad too bad.

Dang guess I am a totally amoral type of guy when it comes to self protection, or the protection of my loved ones.

Including all sorts of things which may make it very expensive proposition to invade my property.
Expensive in not only in a materials type of way.

Cheers Allan


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## ruthiexxxx (Sep 15, 2012)

Aussie Allan In Thailand said:


> Yea funny that,
> 
> It only takes an intermediate knowledge of A & P ( Anatomy & Physiology) to know the make up of vital organ locations of most mammals/zombies.
> 
> ...


Yup...Not too hot on animal anatomy but I guess I've dissected enough humans (dead ones I hasten to add!) to have a good idea of what's where


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## Viper010 (Apr 21, 2012)

@ Aussie Alan

Gotta love the good ol claymore, sooooooooooo much more effective for perimeter defence than the slingshot.

When out hunting though, a slingshot leaves a good deal more to eat...

Each tool has its applications. Be well. Cheers,
Remco


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## Aussie Allan In Thailand (Jan 28, 2013)

Yea Remco, Know more than enough to improvise small shaped charges, then add nuts, bolts, nails etc.

Ruthie, cervical vertebrea, discount top 2 joints or so, as anything above them is goodbye, see ya next life.

Only left with less joint junctions, 7 vertebrea to start means how many joints between them ?...

It is not rocket science people, google it, you have an encyclopaedia at your finger tips.

Cheers Allan


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## ruthiexxxx (Sep 15, 2012)

Aussie Allan In Thailand said:


> Yea Remco, Know more than enough to improvise small shaped charges, then add nuts, bolts, nails etc.
> 
> Ruthie, cervical vertebrea, discount top 2 joints or so, as anything above them is goodbye, see ya next life.
> 
> ...


I don't need to google it Allan Many boring hours during clinical training in the dissection lab taught me all I need to know. And believe me...corpses first thing on a Monday morning, just after breakfast, leave an indelible impression on one's memory ! Dunno why but spinal columns, detached from the rest of the anatomy, seemed the worst somehow. AND I had to know every tiny little part and nerve in bloody Latin just to add insult to injury 

(But perhaps we should leave the discussion in re humans as the Mods will not like it!)


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## Aussie Allan In Thailand (Jan 28, 2013)

Ah the latin part is easy, and pretty dang logical as well.
Well I think so.

In my P.E. training location; there was topless beach near by.

Dang went there often. 
Never opened a text book, but studied alot of A & P..... and even practiced some latin sometimes.

Cunni......what is that word ?....

Is 10.45 pm local time, better go to bed before the Mods. shut me down I think.

Cheers Allan


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## V-alan-tine (Nov 12, 2013)

Seen some youtube vid's where they use Argos catalogues (in UK) for testing crossbows - over 1000 pages


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## Davidka (Jun 8, 2013)

ruthiexxxx said:


> ash said:
> 
> 
> > Water filled soda cans lined up in a row is another fairly reliable measure. I've seen six blown through more than once.
> ...


Forget 'soft drinks', Cruzcampo comes in cans as well! Problem is that water has a tendency to deflect projectiles, and so the phone dir seems like an empiric benchmark.


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## Hrawk (Oct 25, 2010)

ash said:


> Water filled soda cans lined up in a row is another fairly reliable measure. I've seen six blown through more than once.


I see your six and raise you 10.


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## ash (Apr 23, 2013)

Wow, Hrawk! Your slingshot bands sure have a crack to them. Maybe shoot some bigger ammo with it


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## ash (Apr 23, 2013)

ruthiexxxx said:


> ash said:
> 
> 
> > Water filled soda cans lined up in a row is another fairly reliable measure. I've seen six blown through more than once.
> ...


Indeed, perhaps one for the outdoor shooters.

I'm ging to keep my eyes open for phone books and catalogues to shoot at, now.


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## flipgun (Nov 14, 2012)

In any system there is the urge to see, "Just how fast Will this puppy go?" Keep it up. You be the one that gets the record for the most (take your pick) with a rubber powered system. Watching with interest. :headbang:


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## ruthiexxxx (Sep 15, 2012)

flipgun said:


> In any system there is the urge to see, "Just how fast Will this puppy go?" Keep it up. You be the one that gets the record for the most (take your pick) with a rubber powered system. Watching with interest. :headbang:


Yes...pushing things to the max has always been a tendency of mine.But I'm not looking for records or badges. I just want the security of knowing that I have something that will do exactly what I want should the need (Goddess forbid!) ever arise.

But I think I have possibly escalated things as far as necessary now. The starship is right; the rubber is right; the ammo is right. If I have finally standardised things I can now get on with shooting practice to keep improving my aim.


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## bullseyeben! (Apr 24, 2011)

Here's my Nissan Pulsar I shot...
The 3 big dents are .457 lead shot at about 250 fps.
The smaller dents were 8.3 mm lead at 290fps. .
I think if 9.5 mm or 3/8 steel was shot, I may have pierced the panel completely.. yet the soft lead sure can ruin the paint job lol. .


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## ruthiexxxx (Sep 15, 2012)

bullseyeben! said:


> Here's my Nissan Pulsar I shot...
> The 3 big dents are .457 lead shot at about 250 fps.
> The smaller dents were 8.3 mm lead at 290fps. .
> I think if 9.5 mm or 3/8 steel was shot, I may have pierced the panel completely.. yet the soft lead sure can ruin the paint job lol. .


Wouldn't it start? I used to feel like that when mine wouldn't!


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## bullseyeben! (Apr 24, 2011)

Well it's really just my fork drying oven / work car..
45 degree Aussie summers it's me oven... winter was ballistic testing lol..


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## ruthiexxxx (Sep 15, 2012)

bullseyeben! said:


> Well it's really just my fork drying oven / work car..
> 45 degree Aussie summers it's me oven... winter was ballistic testing lol..


A car for all seasons!


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## SuperMonkeySlinger (Jan 28, 2013)

Hrawk said:


> ash said:
> 
> 
> > Water filled soda cans lined up in a row is another fairly reliable measure. I've seen six blown through more than once.
> ...


 Wow man! What was that with?


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## V-alan-tine (Nov 12, 2013)

Hrawk said:


> ash said:
> 
> 
> > Water filled soda cans lined up in a row is another fairly reliable measure. I've seen six blown through more than once.
> ...


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## Wingshooter (Dec 24, 2009)

ruthiexxxx said:


> In a thread I was reading recently (forgotten who/where I'm afraid) the guy said that, in pre-chrony days, people used to test power by penetration into magazines, i.e. how many pages would the ammo pass through. Yay...a quantifiable test procedure!
> 
> I tried it with the fattest, glossiest magazine I could find but that was no help as everything passed straight through it, from hexnuts to the big lead ovals.
> 
> ...


Hi Ruthie

JetBlack and I have been using this method and it shows in a hurry what set up packs the most punch with out doing any calculating. I get dizzy trying to understand all those graphs. We settled on 450 pages of the yellow pages as a bench mark. All paper is not created equal but the yellow pages are universal. In the pictures I am using 13/16 straight cut bands 9 1/2 inches long on my Star-ship. One shot fell a few pages short short but the other went through. Like you I am on the hunt for more yellow pages.


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## ruthiexxxx (Sep 15, 2012)

Wingshooter said:


> ruthiexxxx said:
> 
> 
> > In a thread I was reading recently (forgotten who/where I'm afraid) the guy said that, in pre-chrony days, people used to test power by penetration into magazines, i.e. how many pages would the ammo pass through. Yay...a quantifiable test procedure!
> ...


Wow...that's terrific penetration with a smooth ball. What size/weight ammo were you using?


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## Wingshooter (Dec 24, 2009)

They are 1/2 steel 8.4 gram,129 grain. I shoot them almost exclusively. For me and the setup I use they give me the best all around results speed and power. I don't know the speed but using this phone book penetration test gives me confidence in my setup.


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## ruthiexxxx (Sep 15, 2012)

Wingshooter said:


> They are 1/2 steel 8.4 gram,129 grain. I shoot them almost exclusively. For me and the setup I use they give me the best all around results speed and power. I don't know the speed but using this phone book penetration test gives me confidence in my setup.


One certainly couldn't complain about those results!!


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## coyote-1 (Oct 24, 2013)

Aussie Allan In Thailand said:


> The comparision to lead NOT penetrating is totally misleading.
> The fact it does not penetrate is a good thing actually; as it means that it "dumps" all it's energy at the point of impact
> .
> Making it a near perfect blunt force trauma projectile, as it expends it's total energy very quickly upon contact; ensuring the target "thing" is massively damaged.
> ...


Any projectile that does not penetrate is definitely not expending its total energy on impact. If there is any 'bounce' whatsoever, some energy has been wasted.

The point of impact makes a big difference for us, as our projectiles don't travel very fast compared to other weapons. Head shot? Best bet is likely heavy split lead; penetration is not so important. But a body shot? As zombies are typically not naked, there will be some impact absorption by whatever rags they are wearing, AND blunt force alone won't generate a knockdown. So a projectile that has serious penetration is desirable.


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## Aussie Allan In Thailand (Jan 28, 2013)

Sort of agreed above.

But I will be dammed if I will don a kevlar vest, and let anyone shoot me with my weight of ammo, and band stretch percentage; at any distance less than like 2 miles.

Says he knowing his 12,mm lead penetrate like 4 plus inches into soft tissue areas of mammals at 20 meters.

Cheers Allan


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## benzidrine (Oct 14, 2013)

coyote-1 said:


> Aussie Allan In Thailand said:
> 
> 
> > The comparision to lead NOT penetrating is totally misleading.
> ...


Sorry to disagree but this is incorrect.

A projectile bouncing back from the target imparts significantly more energy on a target then penetration does. Think of it this way a steel ball headed towards a target, it has a momentum headed in one direction and if it hits the target and then bounces backwards, this backwards direction's momentum is in a way coming from the target because it is now traveling in reverse of the way it was travelling before. For every action there is an equal and opposite reaction so for a projectile to have the energy to go in reverse by bouncing it has to impart that energy on the target it hit.

Think of it this way when you are hammering a nail and you hit the nail and you feel the hammer bounce back in you hand after impact, you didn't decide to bounce the hammer back that energy was imparted from the nail's opposite force. Now if you tried to hammer in the nail with a piece of wood even it weighs the same as the metal hammer it is going to be much harder because the nail head will penetrate the wood each time and limit the bounce.

It is a common mistake people make.

Of course for the most part penetration is more deadly to large mammals because we have blood and organs inside us to lose so it isn't all about energy to us. In that I would much rather be hit by a super fast bouncy ball than a bullet travelling at the same speed and with the same weight as the bouncy ball. The bouncy ball is guaranteed to impart more energy but in a way the human body can survive while the penetration of the bullet stands a good chance of penetrating a vital organ. In a very limited sense the human body is a bit like a big bag filled with water, punching the bag of water is less dangerous for the water inside then stabbing it with a nail.


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## coyote-1 (Oct 24, 2013)

Benz, gotta disagree.
The bounce-off is wasted energy; it is not absorbed entirely by the target. Will do a bit of calculating after dinner for you.


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## Aussie Allan In Thailand (Jan 28, 2013)

Hey all, All this is interesting to myself, but only in an intellectually way.

Given I know with my ammo weight, and band set, along with my accuracy.

Practically nothing on legs is getting up, if not dead outright, from any of my shots, even if a few mm of exact point of impact; from 50 meters.

This is more than adequate for my personal desireds.

Given although video will NEvVer be shown for my own reasons.
Mycaccuracy to with in half an inch with very heavy shot ensures if not a clean kill, disableing for a long time.

Cheers Allan


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## coyote-1 (Oct 24, 2013)

The equation is
F = 1/2 m v(squared) / s

Where

W = work done (J, ft lb)
F = slow down force (N, lbf)
s = slow down distance (m, ft)

If the slowdown distance is zero, no work is done. The energy of impact might be higher, but less of it actually gets transmitted to or absorbed by the target.

To return to your nail example: if you strike a nail and it does not move but the hammer bounces straight back off of it, no work has been done! The target has not absorbed that energy, it has instead deflected the energy. This applies to tanks, where armor plate is designed to bounce the exploding shell off the tank rather than absorb that energy (which would be fatal to the crew).

No.... when shooting something, you do not want your ammo to bounce off. You want penetration. Or if not outright penetration, you want the target to deform to a degree that the ammo does not bounce back at all. Else some of the energy has been wasted.


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## benzidrine (Oct 14, 2013)

Obviously you are free to believe whatever you want but this is far from correct.

The correct formula for Work is W = F x d

Where W = Work, F = Force and d = distance. Your formula didn't match your legend, having no W in it.

Of course I have no idea why you tried to post that formula as it isn't what we are interested in.

When dealing with collisions of this type we are primarily interested in the impulse. Ft = △(mv). As in Force of Time equals change in momentum.

Now momentum is a vector quantity meaning that it is relative to direction. If a steel ball hits something and bounces back in the opposite direction it changes it's momentum to a negative in relation to its previous momentum. Therefore the net change is higher and more force is applied.

Think of it this way: does it take more energy to stop a car or to stop a car and then reverse for 1 mile?

You can rearrange the formula like this F = △(mv)/t. In that force equals change in momentum over time. If the momentum of a steel ball is 1 and hits something and it comes to a full stop in 1 second then the force is 1 Newton.

If the momentum is 1 and it rebounds on impact at half the momentum in the opposite direction then the change in momentum is 1.5 and if it took 1 second to rebound it is 1.5 Newtons of force.

"if you strike a nail and it does not move but the hammer bounces straight back off of it, no work has been done!"

Well obviously work has been done, the work is in relation to the hammer.

Read this its pretty simple and should help you understand: http://wps.pearsoncustom.com/wps/media/objects/3713/3803102/SCI321_Ch03.pdf


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