Pressure problem but without any given values. How?

  • Thread starter Thread starter evilrain14
  • Start date Start date
  • Tags Tags
    Pressure
AI Thread Summary
The discussion revolves around determining which dam, holding back a large lake or a narrow river, needs to be built more strongly. The consensus suggests that the second dam, which holds back the narrow river, requires greater structural integrity. Participants express a need for mathematical proof to support this conclusion, particularly in the absence of specific values. The concept of hydrostatic pressure is acknowledged, along with the mention of the hydrostatic paradox, which may provide insight into the problem. Ultimately, the focus is on finding a way to demonstrate the reasoning behind the strength requirements for the dams.
evilrain14
Messages
5
Reaction score
0

Homework Statement


Both dams equally wide and equally high. The first dam holds back a very large lake, and the second dam holds back a narrow river.


Homework Equations


Which dam has to be built more strongly?
a.) the first dam
b.) the second dam
c.) both


The Attempt at a Solution



i know it would be the second dam that holds back a narrow river, but how can i prove it mathematically/algebraically?
how can i show the answer in ratio? -.-

i need your help please.

thanks!
 
Physics news on Phys.org
Do you know what the hydrostatic pressure is?
 
yes. but my problem is, there is no any given values/numbers. i know what to answer but i can't prove it.. :(
 
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
View full post »

Similar threads

Calculate Pressure on a Dam: Answer 0.33
Replies
3
Views
4K
Dam Failures and Infrastructure Damage in a Changing Environment
Replies
8
Views
4K
Calculating water pressure, gauge pressure
Replies
3
Views
8K
Question dealing with density and pressure
Replies
7
Views
2K
Finding the Net Force Exerted by Water (of certain depth) on A Dam
Replies
1
Views
9K
How does a difference in air pressure induce a force?
Replies
15
Views
2K
Force of water against a dam gate
Replies
29
Views
3K
Electricity Homework: Calculating Energy, Volume & Distance
Replies
2
Views
12K
Fluid Mechanics: Worked Out Problem, Check Work?
Replies
1
Views
9K
How long would a lever have to be to compete with a hydroelectric dam?
Replies
5
Views
2K

Hot Threads

Recent Insights

Back
Top