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# Thread: Physics Problem For a Friend

1. ## Physics Problem For a Friend

Maybe someone can help me with this. I have a friend who needs to find the Force or Potential Energy in a typical mouse trap spring. Any Physics masters here who know anything about this let me know. I'm too lazy to look it up myslef.

2. PE=(1/2)kx²

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Protein = 4 cals/gram
Carbs = 4 cals/gram
Fats = 9 cals/gram

~SC~

4. He'll have to know the speed at which the moustrap closes. He'll also need to know the difference in the area it travels from when it's shut to when it will snap down. Essentially, you'll know that the potential is 100% when it's shut, and 0% when it's at full swing. So find those two factors.

5. Originally Posted by rambo
He'll have to know the speed at which the moustrap closes. He'll also need to know the difference in the area it travels from when it's shut to when it will snap down. Essentially, you'll know that the potential is 100% when it's shut, and 0% when it's at full swing. So find those two factors.
you need the spring constant

6. Originally Posted by symatech
you need the spring constant
Can't he use F= ma by doing some measures, and then use PE=1/2kx^2 by solving for k?

7. its just PE=(1/2)kx² where x is the distance of compression the spring. k is a constant for all spring its like 8.03x10^-8 i cant remember.

EDIT: let me find my physics one book lol this has been a while.

i dont really know how to approach this question. normally when youre dealing with the potential energy of a spring youre given that it is compress by some mass and you use (mass)(gravity)=k*x and solve for k that way. in a mouse trap its just clipped into position

thats all the info i can tell ya, cause he will have to get a Newtonmeter to figure out how much Force it took to compress the spring and devide by x(the distance the spring was compressed) to get k, then just use PE=(1/2)kx²

if you really want to get accurate, you can go into the angles, since it is not a traditional spring, not a curly thing you push and stretch, rather it has the two arms that coil.
Last edited by Psychotron; 04-08-2005 at 10:22 PM.

8. Depends if the spring is linear(ideal spring)......measure the force of the spring at full open full closed and 90 degrees......see if it is linear. Then I think you could use the moment and spring equation to calculate spring constant. You could use a simple fish weighing scale and then convert to whatever units you want.

OR.....you could stick your finger in it and compare the dent to a known weight with the same diameter wire.......experiments are much more fun.

9. You guys are all right. The main problem he was having is finding the spring constant of a mouse trap. If anyone knows that. He said he looked for it on the internet but couldn't find it.

10. Originally Posted by SwoleCat
Protein = 4 cals/gram
Carbs = 4 cals/gram
Fats = 9 cals/gram

~SC~
Correct!

11. Originally Posted by Psychotron
its just PE=(1/2)kx² where x is the distance of compression the spring. k is a constant for all spring its like 8.03x10^-8 i cant remember.

EDIT: let me find my physics one book lol this has been a while.

i dont really know how to approach this question. normally when youre dealing with the potential energy of a spring youre given that it is compress by some mass and you use (mass)(gravity)=k*x and solve for k that way. in a mouse trap its just clipped into position

thats all the info i can tell ya, cause he will have to get a Newtonmeter to figure out how much Force it took to compress the spring and devide by x(the distance the spring was compressed) to get k, then just use PE=(1/2)kx²

if you really want to get accurate, you can go into the angles, since it is not a traditional spring, not a curly thing you push and stretch, rather it has the two arms that coil.
**** Gilligan that's heavy stuff

Depends if the spring is linear(ideal spring)......measure the force of the spring at full open full closed and 90 degrees......see if it is linear. Then I think you could use the moment and spring equation to calculate spring constant. You could use a simple fish weighing scale and then convert to whatever units you want.

OR.....you could stick your finger in it and compare the dent to a known weight with the same diameter wire.......experiments are much more fun.
That's wrong the spring has to have a density no less then a star plus the mass of a black hole if you are to subtract that with the weight of a pin in the 4th dimension and then multiply that by the space time continuum then you will get the cofactor of time travel therefore the spring must be no less then .3 minus the IQ of Axe which is -35 add those together and you will find an answer.

See physiques aint so hard