[TheForge] Re:Mass vs. acceleration vs. soil (A Novel)

[Peter Fels And Phoebe Palmer]

Hello Thomas;
You are the man who knows about this stuff....thank you for chiming in.
Well, I guess that settles that, and settles that, and settles that, and 
settles that, and settles that, pretty certainly.
Your arguments are convincing..excellent...but my hand still hurts.
Mass it is... am I correct in assuming  high strength reinforced 
concrete will do? It'll be a lot  cheaper than  a massive slab of 
steel..(I'm assuming).
Though I wouldn't mind getting out of all that digging, I'll admit.
Let's see...time spent digging and reinforcing and mixing mud + the cost 
of cement and aggregate....mmmmmmm..it's getting cheaper fast.
Your expertese is greatly appreciated Tom !
And thanks to all who contributed and saved me from another hairbrained 
scheme!.......Pete

Thomas A. Troszak wrote:

>>From: Peter Fels And Phoebe Palmer <artgawk@thegrid.net>
>>I've been giving a lot of thought  to the foundation to go under the
>>hammer, as you might imagine.
>>My tentative plan is to dig deep and pour a couple of yards of
>>reinforced concrete, put in a layer of timbers topped with another yard
>>of concrete. On top of that I plan to stack alternating layers of
>>plywood, cork, steel, rubber,  4"wood slab and more timbers.
>>The theory is that different layers of materials will tend to damp
>>different frequencys of vibration and the cold shut effect will be
>>compounded by having all those different layers.
>>    
>>
>
>Dear Peter and Phoebe,
>No, no, no, no, no. Please read the following.  :)
>
>  
>
>>From: GHS <ghs@execpc.com>
>>Tom Troszak, are you out there? This arrangement sounds much like the
>>one that gave me so much grief. I lost your explanation or I would just
>>post it here.
>>    
>>
>
>
>Dear Peter and Phoebe and Mike,
>
>The solution is very simple, but perhaps not simple to explain why. There
>are two distinctly different things happening here, what is going on in the
>hammer, and what is going on in the soil.
>
>First, what is going on in the hammer:  Think of the anvil as a mass
>floating in space, because that is what it is. When we strike the anvil with
>a mass (such as the ram) the anvil accelerates in space as a ratio of the
>mass of the ram (and the the velocity of the blow), vs. the mass of the
>anvil.   
>
>An analogy: Ever played croquet? You know how you can "launch" your
>opponent's croquet ball clear out of the game if your ball is touching it,
>by smacking your ball with the mallet. The blow from your mallet accelerates
>your ball (which decelerates the mallet) which then strikes the opponent's
>ball (which decelerates your ball) and accelerates the opponent's ball clear
>out of the yard (about thirty feet).
>
>Now think of the mallet as the "ram", your ball (under your foot) as the
>"anvil", and the opponent's ball as the "soil". If the mass of the "anvil"
>(the ball under your foot) is nearly the same as the "ram" (the mallet), it
>will accelerate to nearly the same velocity as the "ram" (the mallet), and
>pass that acceleration on the the "soil" (the opponent's ball) at high
>speed. 
>
>Let's try the experiment again, but substitute a bowling ball for the
>"anvil" under your foot. The 16 lb. bowling ball "anvil" has a mass about
>thirty two times greater than the 1/2 lb. mallet "ram".
>
>Smack the bowling ball with the mallet, and it will accelerate, but only to
>1/32 of the velocity of the mallet, so when the bowling ball "anvil"
>collides with the "soil" (the opponent's ball), it does so at only 1/32 of
>the original velocity of the mallet, so that the "soil" (the opponent's
>ball) only launches about 1/32 as far (about a foot).
>
>The total energy of the blow of the hammer ram is not "absorbed" by the
>anvil, it is transformed into a lower velocity of acceleration of the anvil.
>Since the anvil is accelerating more slowly, the the soil is "struck" more
>slowly, and the resulting "shock wave" has less velocity.
>
>Still with me?
>
>Ok, try these Mind Experiments (but don't actually do them, I cannot me held
>liable for injuries):
>
>Take your favorite 2 lb. hammer and smack the palm of your hand. Ouch.
>(remember I said don't really do this, just think about it)
>
>Now place your palm on one end of a brick and smack the other end of the
>brick with the hammer. Ouch.
>
>Now place your palm on one end of a two foot long pine 2x4 and smack the
>other end of the 2x4 with the hammer. Ouch.
>
>Place your palm on one side of a piece of plywood, and smack the other side.
>Ouch.
>
>Place the end of the 2x4 against the end of the brick, palm at one end,
>hammer at the other. STILL Ouch.
>
>
>Now change things a little:
>
>Place your palm on one side of your anvil and smack the other side. Ting. No
>ouch.  
>
>Why?
>
>The wood and bricks (concrete, croquet balls,) etc, are fairly rigid, yet
>not very dense, so they conduct high velocity shock waves fairly
>efficiently. If you have ever held a board while someone was nailing on it
>you know what I mean. They do no (or very little) good as absorbers of shock
>waves because they participate in the propagation of the shock wave with
>great enthusiasm. 
>
>What to do? Slow down the velocity of the shock wave at the source: the
>anvil. The heavier the anvil, the slower the wave, as in the croquet
>experiment. One caveat: the anvil has to be one big fat piece, not a stack
>of loose plates. Why?
>
>If you set a row of billiard balls about 1/4 inch apart (or even touching)
>and shoot the first ball... craaaack and the last ball shoots away nearly as
>fast as the first was shot. Same goes for those little hanging ball
>bearings, or a row of dominoes, empty freight cars in a train or whatever.
>The acceleration is transferred from object to object with little loss of
>velocity as each object accelerates with the nearly same velocity, and the
>shock (actually acceleration) wave passes right along.
>
>Now place the bowling ball (left over from the croquet experiment) gently on
>the billiard table, and shoot it with a billiard ball. Click. Yep, the
>bowling ball moved, but probably too little to even see. Just like the
>anvil.
>
>Ok, enough of analogies. Firmly bolt your power hammer to a single thick
>plate of steel, say a minimum of 20 times the mass of the ram.   If you have
>a 100 lb hammer, then use a 2000 lb. plate minimum.  More is definitely
>better, up to about  35/1 ratio. The hill (as well as the wine glasses on
>your pantry shelves) will not even know your hammer is there. Save all that
>digging.
>
>Question: If all 1,000,000,000 Chinese stood up on chairs and jumped off at
>the same instant, would Peter's house slide into the sea?
>
>Answer: No, but that is a different question for another time...
>
>I hope this is helpful.
>
>Tom Troszak
>
>
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