## Re: cost of lunch

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• ... bend, and that can be right next to the end, or in the middle. If the greatest force is near an end, the curve will continue to the end. The bending moment
Message 1 of 12 , Jan 1, 2002
> The sharpest bends will be where the greatest force to cause the
bend, and that can be right next to the end, or in the middle. If the
greatest force is near an end, the curve will continue to the end.

The bending moment at any point is the product of the applied force
and the effective lever arm. As you get to the end of the piece of
wood, the lever arm disappears, and so does the bend. So, it is easy
to get a little bend in the middle of a 2x4, but not in the last
couple of inches at the end.

PHV
• Peter: Remember the fun we had with mental experiments with water ballast a year ago? Here is a new one: Take a 2x4 and bend it any way you want. Now
Message 2 of 12 , Jan 1, 2002
Peter:

Remember the fun we had with mental experiments with water ballast a year ago? Here is a new one: Take a 2x4 and bend it any way you want. Now imagine it suspended in the air. Now mask off all but a six inch section of the plank. I challenge you to see the curve in that section, or to determine whether it is in the middle or on the end. The point is that with these slight curves, you can only determine that there is a curve by looking at the plank beyond the curve.

I agree with what you say about lever arms, but it is possible to take a limber plank (like a narrow piece of plywood) and present it to a boat in such a way that it is straight in the middle and more curved toward the ends - like a canoe, for instance.

Chuck
> The sharpest bends will be where the greatest force to cause the
bend, and that can be right next to the end, or in the middle. If the
greatest force is near an end, the curve will continue to the end.

The bending moment at any point is the product of the applied force
and the effective lever arm. As you get to the end of the piece of
wood, the lever arm disappears, and so does the bend. So, it is easy
to get a little bend in the middle of a 2x4, but not in the last
couple of inches at the end.

[Non-text portions of this message have been removed]
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