Krotov problem: how to write Energy conservation for this fluid?

Click For Summary

Homework Help Overview

The discussion revolves around the Krotov problem, specifically focusing on the application of energy conservation principles in fluid dynamics. Participants are examining the relevance of certain parameters, such as the radius derived from the cross-sectional area of the fluid.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants are questioning the validity of the radius calculation and its relevance to the problem, particularly since it is not explicitly provided in the problem statement. There are discussions about the implications of using the center of mass for fluid parts and the assumptions regarding the cross-sectional area.

Discussion Status

The discussion is ongoing, with some participants seeking clarification on the relevance of the radius and others pointing out potential errors in the initial calculations. There is an emphasis on the need for participants to share their working to facilitate better understanding.

Contextual Notes

There is a mention of forum rules requiring participants to post their working, which suggests that the problem may involve specific constraints or assumptions that need to be made explicit for effective discussion.

ermia
Messages
13
Reaction score
0
Homework Statement
I uploaded the problem. when I want to write the potential energy of the fluid in the initial and final state I don't find the right answer. I know the rest of the problem.
Relevant Equations
$$ U=\rho g h A h_{cm} $$
I wrote some potentials but they were wrong. I used the cm of all fluid parts and I used the radius which is $$ \sqrt S/ \pi $$ .
 

Attachments

  • Apt.jpg
    Apt.jpg
    40.7 KB · Views: 133
Physics news on Phys.org
That equation for radius has a "type" error.
$$r =\sqrt \frac{S}{\pi} $$
 
Per forum rules, please post your working. Otherwise we have no way to know where you are going wrong.
 
Could you explain how is that radius, which is not shown as data in the problem, relevant?
 
Lnewqban said:
Could you explain how is that radius, which is not shown as data in the problem, relevant?
S is the cross sectional area, so ##S=\pi r^2##. But if you are asking why bother calculating the radius (you don't even have to assume it is a circular cross section) then I agree.
 
  • Like
Likes   Reactions: member 731016 and Lnewqban

Similar threads

Replies
2
Views
1K
  • · Replies 12 ·
Replies
12
Views
1K
  • · Replies 9 ·
Replies
9
Views
1K
Replies
28
Views
2K
Replies
24
Views
4K
  • · Replies 20 ·
Replies
20
Views
3K
Replies
15
Views
2K
Replies
15
Views
2K
Replies
55
Views
5K
  • · Replies 4 ·
Replies
4
Views
2K