'Perception of the amount of weight' is pretty much nonsense, because that would depends on just how strong the person is. 40lbs feels like a lot to a little girl, and like nothing to a weightlifter. How it 'feels' would also depend on how it's being lifted: one a point, or spread across a bar, say. So the 40lbs 'feels' like a lot more if you used only your rope, versus if you spread the force of gravity pulling on the bucket over a solid steel bar, and then lifted the bar. This is because the load is either all on a single spot, or spread out over an area.

Consider the weight of your body when you stand flat on your feet, versus standing on your toes. You 'feel' a lot heavier, even though you weigh exactly the same.

It's still 40lbs, and that never changes on the scale you are referring to. What you are really asking is entirely subjective, and pretty stupid.

 

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Centripetal acceleration will cause a change in the weight of a mass resting on the earth's surface. As you approach the equator, this acceleration increases in value. The equatorial radius of earth is approximately 6400 km, with a rotational period of approximately 24 hours. Using the formula (4 * pi^2 * r/T^2), and converting hours to seconds, you arrive at a centripetal acceleration of approximately .03 m/s^2 at the equator. A given mass, on the equator, is subject to both this centripetal acceleration and acceleration due to the force of gravity. An object resting on the surface of the earth at the pole of the spin axis is not subject to the centripetal acceleration.
The oblate shape of earth also contributes to changes in gravitational force as a mass moves along the surface between the equator and either pole. The gravitational force and the distance between two objects share an inverse square relationship. Using the accepted formula for the gravitational force between two objects, F = G*(m1 * m2)/r^2, with G being the gravitational constant, one can see that the magnitude of the force value will change with latitude. When appropriate mass and radius values are substituted into this equation, you arrive at equatorial and polar acceleration values of approximately 9.78 and 9.83. The weight difference is about 0.5%. So for a 100 kg mass on the pole, a shift to the equator would account for a decrease of .5 kg. In the case of the 40 pound bucket? You do the math. In the context of a mass resting on the surface of the earth, it is also true that the density and composition of the material that the mass is resting on ( in a straight line from the surface all the way to the exact center of the earth ) will effect the force, but the value of that change is usually less than 0.01%. Geological formations near the mass on the surface can also have a very, very minute effect. Moral of the story: Altitude matters because radius matters. Latitude matters because radius matters. In the case of a 20 ft rope? The difference is gravitational acceleration is obviously less than negligible.
But anyhow, the real argument here is a matter of work done on a mass, and this can be conceptualized by thinking about the work that would need to be done against gravity to raise a bucket. If you grab a bucket with one hand and lift it a distance of 10 meters, a certain amount of work is being done against gravity. The same can be said if you are holding on to a 20ft rope attached to the bucket. The real meaningful difference is just the different groups of muscles and different lengths of contractions involved in the two scenarios. Friar asked, "How much does the perception of the amount of weight make it seem like is being lifted?" I guess the only real answer is this: It just depends on the person and how they lift stuff.

 

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HERE IS THE ANSWER THAT YOU WANT:

80years x 40lbs x 20ft = 64000lbs

WOW!!! YOUR UNCLE IS SO FUCKING STRONG!!!

 

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You forgot to put that into the proper measurement of footyearpounds.

 

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Are you seriously asking if there is a "wind Chill Factor" for lifting weight?

Where is Sweeney? he could have saved us all this aggravation and answered this question pages ago.

 

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This is the likliest answer - the stress points on a human body for achieving the 'easiest' lift vary as the bucket swings and this DOES make the bucket 'feel' heavier. A lift between the legs is the least likely to have this effect, one while bent over the well opening the most.

 

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only on the outpost could this be a 50 + post discussion.

Let's just push Friar down the well when he goes to test his theory.

 

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