How do hammer and nails transfer energy?

  • Thread starter whitelighter
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In summary, the conversation is discussing the transfer of energy from a hammer to a solid object. There is debate over the time involved in this transfer and whether quantum mechanics needs to be taken into account. The uncertainty principle and the speed of cause and effect are mentioned. The impact of a hammer on a nail is used as an example, with some suggesting that the nail follows Hooke's law. The elasticity and inelasticity of the collision are also considered. The practical application of this conversation is brought up by a tradesman, who is wondering why a lighter hammer can drive nails just as well as a heavier hammer, and why steel becomes more brittle at high impact speeds.
  • #1
whitelighter
Maybe some one can clear something up with what current theory is.

If you take a hammer and you hit a solid object, how much time is involved in the transfer of energy from the hammer and or to the solid object?

This is prompted by the dev. in another thread that questions the speed of Cause and effect.
 
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  • #2
Do we have to use QM? If so, we run up against Heisenberg's Uncertainity Principle. The minimum time that we can meaningfully discuss if QM is correct here is the Planck time, which is about 5.4 e-44 sec. Otherwise, the answer is, it depends!
 
  • #3
I definitely think it's "otherwise" :smile: .
 
  • #4
And I definitely think it "depends." So we're all in agreement! =]

cookiemonster
 
  • #5
I think possible my question is a bit silly in that it's all about picking straws...

For energy to transfer it has to transfer yes?

The start of transfer to the end of transfer. The start being the start and the end being the end.

hmmmmm...Instantaneous start but a slower end maybe
 
  • #6
This isn't all that hard to find out: pick a nail size and material, a hammer weight and speed and do the spring energy calculations. You can probably ignore the elasticity of the hammer, just model the nail as a spring.
 
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  • #7
Russ,
Are you saying that carpenters and brick masons can just ignore the effects of quantum mechanics and general relativity and still be able to do their job? LOL
-Mike
 
  • #8
The Uncertianty Principle! Now I understand. The motion of the hammer means we cannot know where it is! Thus it is imposible to hit a nail with a hammer!

and I have experimental Proof! (Just look at anything I ever nailed) With a hammer of course!
 
  • #9
Integral,
God doesn't play dice with my thumb, I get it every time.
-Mike
 
  • #10
ha ha maybe I should have use a balloon instead of a nail...
 
  • #11
russ waters said: "just model the nail as a spring."

A spring? I would think this is nearly a perfectly inelastic collision. The hammer's kinetic energy goes to zero at which point the nail has been driven in some distance s, defined by:

KE(hammer) = integral(dp/dt(hammer)*ds) - a (very small) increase in hammer's thermal energy
 
  • #12
jdavel said:
russ waters said: "just model the nail as a spring."

A spring? I would think this is nearly a perfectly inelastic collision.

Russ isn't as dumb as he looks. LOL. Russ doesn't miss much. Think about it. Russ is saying that the nail follows Hooke's law.
-Mike
 
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  • #13
whitelighter said:
Maybe some one can clear something up with what current theory is.

If you take a hammer and you hit a solid object, how much time is involved in the transfer of energy from the hammer and or to the solid object?

This is prompted by the dev. in another thread that questions the speed of Cause and effect.


No greater than the speed of sound for the contact medium impacted.
What occurs on impact is a "shock wave"
 
  • #14
Well, actually, I guess it is more complicated: you have two things going on, not just one. I didn't take the thought all the way (lazy). The nail-hammer part is near perfectly elastic, the nail-board part is near perfectly inelastic.

edit: reading the first post again, the author just says "an object" - so it could be just about anything. Elastic/inelastic will depend on the object. Either way though, its still not a difficult problem.
 
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  • #15
Actually Russ, I was going to use the example of a block of iron say 10 cccm hittng a similar block of iron.

The answer SEEMS obvious to me but I have been soooo wrong before which is why I ask it...

With out quoting some ones theories I would assume that energy is tranfered from one block to the other in full at the point of impact ( assuming the receiving object is held in a ridgid position as in non- movable)

You know that little mobile with the balls on strings that clack clack away until gravity peels of all the inertia.

One ball hits a row of say 5 other balls the ball on the opposite side reacts immediately the first ball hits...is the assumption that I want to clear up

Actually the Mobile of the balls is a good example of the fundamental I want to explore
 
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  • #16
russ_watters said:
...reading the first post again, the author just says "an object" - so it could be just about anything. Elastic/inelastic will depend on the object. Either way though, its still not a difficult problem.

You're right. I read the title of the thread and never stopped thinking about the object as a nail.
 
  • #17
I'd like to revive this thread for a practical purpose. I'm a tradesman with a hobby interest in science, and a most practical application for the original question.

If you only look at the problem as 1/2 MV^2 the theory doesn't match the actual result. I was reading Wikipedia and they were discussing titanium hammers, and how the lighter head swings faster, making it easier to drive nails. I own a titanium hammer and a regular framing hammer. While the Ti hammer is OK for driving nails, if you need to move something heavy like a wall, it doesn't matter how fast you swing the hammer, the wall doesn't move.

What I'm wondering right now is why is there a difference in the result between a heavy mass moving slowly compared to a light mass moving quickly even if the math says the force should be the same?

Also, at really high impact speeds why is steel more brittle?
 

1. How do I use a hammer and nails?

Using a hammer and nails is a simple process. First, hold the nail with your fingers or use a pair of pliers to hold it. Then, place the nail on the surface where you want to hammer it in. Hold the hammer with your dominant hand and place the nail head on the surface. Using controlled force, strike the nail head with the hammer until it is securely in place.

2. What is the best type of hammer for using nails?

The best type of hammer for using nails is a claw hammer. It has a flat striking surface and a curved claw on the back for removing nails. The weight of the hammer should also be considered, as a heavier hammer can provide more force for driving nails into tougher materials.

3. How do I choose the right nail for my project?

The type of nail you choose depends on the material you are nailing into and the weight of the object you are hanging. For lighter objects, a thin nail may be suitable, while heavier objects may require a thicker or longer nail. Nails also come in different materials such as steel, brass, or galvanized, so consider the material of your project and the potential for rusting.

4. How can I hammer in a nail without damaging the surface?

To prevent damaging the surface you are nailing into, place a small piece of scrap wood or a nail holder between the hammer and the surface. This will absorb some of the impact and protect the surface from any dents or scratches. You can also use a nail punch to drive the nail in further without damaging the surface.

5. How do I remove a nail that has been hammered in incorrectly?

To remove a nail that has been hammered in incorrectly, use the claw of a hammer to grip the nail head and pull it out. If the nail is too short to grip with the claw, use a pair of pliers or a nail puller to remove it. If the nail is stuck, try tapping it lightly from the opposite side to loosen it before pulling it out.

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