Recent content by Novus

I do not intend to build anything. Solving Fb for the total volume of the object (note that in this case calculating Fb as the difference between the top and bottom area does not work); Fb = V * p * g = 18 cm3 * 1 kg/m3 * 9.81 m/s2 = 0.1766 N. For the downwards hydrostatic force on top of the...

The laws of thermodynamics and the law of conservation of energy are important fundamental laws of physics in general. A perpetual motion machine is therefore impossible, as it would violate either the first or second law of thermodynamics. As I already explained I became interested in...

To summarize what has been concluded so far; Post 25 - 'Because the object is not surrounded by fluid on all sides, Archimedes law does not apply. The net force from fluid pressure must be calculated from first principles rather than from the weight of the displaced fluid.' Post 25 - 'I...

In post 26 I calculated positive Fb for both scenarios. In addition, as per the original description, the object consists of solid area's with the same density as water and a 'pocket' of air, therefore the overall density of the object will be less than the density of the surrounding water. I'm...

This would than be the same calculation as per my suggestion in post 26 I believe.

Good point. See attached calculations for the water's center of mass for the original scenario (3.324 cm from the top) and for a second scenario where the object has moved upwards by 2cm resulting in a shift of the center of mass to 3.831 cm from te top down. If these calculations are correct...

Using the method in attached file ('buoyancy calculations') the resulting Fb for the scenario would be positive. F1 = h1pgA = 4pg10 = 40pg F2=h2pgA = 6pg8 = 48pg Fb = F2 - F1 = 8pg When the trapezium moves upwards 2 cm the resulting Fb would be F1 = h1pgA = 2pg12 = 24pg F2=h2pgA = 4pg10 =...

I agree that, obviously, P.E. can not increase without an external input of energy, however I'm not sure if this is neccesarily the case when the object would move upwards - see attached "P.E. scenario's picture" Please find attached picture ("example object movement") with one possibly way on...

I'll try to come up with a better description (which probably needs a picture) on how the sides of the trapezium shaped object are water tight connected to the side walls of the container and yet can freely move up and down. Why? The area * dept at the bottom > the area * dept at the top and...

Wouldn't the P.E. of the object, when moving upwards decrease in comparison to the initial lower position? The air is connected to the outside air, and since there are no lateral forces, nothing will happen to the air? In other words there are no forces, except for the atmospheric pressure of...

Correct, apologies if this was not clear - probably as a result of the fact that english is not my native language.

I understand that the objective of the forum is to educate the user by asking questions. Based on the scenario the object would move upwards since (i) the forces on the top and bottom of the object are directly related to surface area * dept and (ii) the density of the object < density of water...

"If there was a side channel for the water to move from above to below, then the object would move up." Anyone else agrees based on the understanding that in this case the volume of air contained as part of the object would increase?

Since the density of the object > density of air it would move down if there is no water in the container.