School task in physics
Hello,
I propose to your court the following problem for a school course in physics.
A vessel with water was placed on the scales, and a wooden bar was placed in the water. The bar floats on the surface. The water level in the vessel, naturally, rose. After the bar was taken out, the waters were poured into the vessel to the level that was in the vessel together with the bar. In which case will the scale show more weight - with a floating bar or with added water?
The answer is under the cut
UPD: To be honest, I came up with this problem, not having 100% confidence in my decision. And later I became convinced that my decision was incorrect. The right decision was voiced many times in comments:
')
The bar remains to float on the surface, partially submerging in water. According to Archimedes' law, the weight of a bar will be equal to the weight of water taken in the volume of the part of the bar completely submerged in water. If you now mentally remove the bar, “leaving” a recess in the form of a bar in the water, and fill this recess with water, the water level in the vessel will rise to the desired level. The weight of the added water is equal to the weight of the bar and the scale, therefore, will show the same weight.
I propose to your court the following problem for a school course in physics.
A vessel with water was placed on the scales, and a wooden bar was placed in the water. The bar floats on the surface. The water level in the vessel, naturally, rose. After the bar was taken out, the waters were poured into the vessel to the level that was in the vessel together with the bar. In which case will the scale show more weight - with a floating bar or with added water?
The answer is under the cut
UPD: To be honest, I came up with this problem, not having 100% confidence in my decision. And later I became convinced that my decision was incorrect. The right decision was voiced many times in comments:
')
The bar remains to float on the surface, partially submerging in water. According to Archimedes' law, the weight of a bar will be equal to the weight of water taken in the volume of the part of the bar completely submerged in water. If you now mentally remove the bar, “leaving” a recess in the form of a bar in the water, and fill this recess with water, the water level in the vessel will rise to the desired level. The weight of the added water is equal to the weight of the bar and the scale, therefore, will show the same weight.
Source: https://habr.com/ru/post/97679/
All Articles