## How to find the normal stress and strain!!

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### How to find the normal stress and strain!!

Hello i am trying to complete the You Nailed It! Hammering Force for Different Types of Wood project and i am having trouble trying to determine the normal force that hammer exerts on the wood. How do i find the normal force on the wood so i can calculate the normal stress and strain on the wood.

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hdilber

Posts: 1
Joined: Mon Oct 22, 2012 1:06 pm
Occupation: student
Project Question: On the You Nailed It! Hammering Force for Different Types of Wood project. How do you calculate the actual force that is being applied to the wood. Then how would i find the normal stress and strain on the wood? thanks in advance
Project Due Date: November 23, 2012
Project Status: I am conducting my research

### Re: How to find the normal stress and strain!!

Hello hdilber,

I assume you have built an apparatus as described in the project description. That apparatus is not sufficient to measure the properties you want.

Given a hammer of a certain weight and handle length, you could calculate how fast the hammer is traveling when it hits the nail using high-school physics. What happens then?

The force exerted on the wood depends on how fast the hammer accelerates the nail and then on how fast the wood friction slows it down. You would need an accelerometer mounted on the nail to measure these data. That would make a nice experiment, but do you want to extend it that far?

The exact forces will also depend on the properties of the nail. What is the tapering angle of the nail point? How does the nail material affect the friction of the nail/wood interface?

I don't want to discourage you from extending the experiment, but be careful about how much time it will take.

Good luck, WW
wendellwiggins
Expert

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Joined: Sun Jul 10, 2011 5:48 pm
Occupation: retired physicist
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