Originally posted by jemidiah
It also depends on how you measure the weight. If you're going by downward pressure on the rope, then it will be least in the air, next in the shallow water, and finally most heavy in the deep water. This is because of water (and air) pressures. If you measure the true weight, then they would all be the same.
True weight? You mean mass?

Also we basically come to the same results; I myself said that the weight will not change while most of the others said the rock would get heavier in deep water. That I just don't get, water pressure would be acting on the rock from all sides, and so while it will increase with depth, it cancels itself out and does not cause the tension in the rope. As much as I tried to explain that people still said that it will get heavier so I'm kind of hoping that someone will do a better job of explaining one or the other then we were. As far as I see it, gravitational force does not change, the reason that rock is lighter when first submerged into water is due to buoyancy and the weight of the water displaced is subtracted from the rocks weight. Buoyancy force does not change with depth because the volume displaced is still the same as it was before, therefore, the only other force is tension and that should stay constant as long as the other two do.

Agree? Disagree?

Originally posted by alkatran
If you're holding it there with a rope it has 0 weight .
Damn, that must be only true in Canada j/k