Force calculation
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Posted by: growch ®

12/21/2006, 16:05:10

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Hi folks. I have a equation for you to solve. I'm sure its elementary to you but I'm stumped and the online calculators aren't quite supporting my situation. Here goes....
L = LEVER
F= FULCRUM
U= UNKNOWN FORCE by gas springs.

LLLLLLLLLLLLLLLLLLLLLLL
U F

LEVER WEIGHS= 60 POUNDS distributed evenly
DISTANCE FROM U TO F = 5.5"
DISTANCE FROM F TO END OF LEVER IS 70"

What is the equation for this? Better yet whats the answer! I need to find equilibrium so the lever can be raised with 0 force.

Thanks in advance.








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Re: Force calculation
Re: Force calculation -- growch Post Reply Top of thread Forum
Posted by: swearingen ®

12/21/2006, 17:03:06

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Well, first, the lever can't be raised with 0 force. Some force will have to be applied by the U (unknown force) to raise the lever. The trick here is that you can approximate this situation by concentrating all of the weight of the lever at its center. So, you'll have a weightless lever with a fulcrum and an applied load of 60 pounds 32.25" from the fulcrum. You should be able to get it from there...







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Re: Re: Force calculation
Re: Re: Force calculation -- swearingen Post Reply Top of thread Forum
Posted by: growch ®

12/21/2006, 17:14:22

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Yes, your right and I understand that there will be a force to raise the lever. But very little. I came up with 392.72 lbs of force. Is this right? Or close. My formula is:

W = Weight of object to be moved (lbs.).
Y = Distance from fixed mounting point to center of the object (inches).
Z = Distance from hinge point to
moving mounting point (inches).
W x Y / Z

Go ahead tell me how wrong I am.

thanks








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Re: Re: Re: Force calculation
Re: Re: Re: Force calculation -- growch Post Reply Top of thread Forum
Posted by: swearingen ®

12/22/2006, 07:59:44

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The equation is right, but I don't know what happened when you plugged the numbers in. W should be 60lb, Y should be the 32.25" (which equals (70+5.5)/2 - 5.5, i.e. the distance from the fulcrum to the center of mass of the lever), and Z should be the 5.5". Try the math again.

Now, if you want to add something to the end of the lever, the equation changes to:

(W*Y + W2*Y2)/Z, where the W, Y and Z are the same as before, and the W2 and Y2 are the weight you added and the distance between that weight and the fulcrum, respectively.








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